While we never got to the bottom of that issue (I couldn't reproduce it), it's worth backing up and examining font use on the web.

Fonts, unlike any other aspect of web browser rendering, depend on the platform, not the browser version.

The reason is simple: fonts are not bundled with the browser, but with the operating system, or installed with some creative applications.

If you select fonts based on how they look on your computer, they will look different on another computer with a different set of fonts installed. Also, fonts are matched by name in CSS, so when you write

font-family: "Helvetica", "Arial", sans-serif;

you are requesting a font named "Helvetica", then one named "Arial", then the default sans-serif fonts. This is a very common thing for people to write, because Helvetica is a popular choice on Mac, Arial is a popular choice on Windows, and sans-serif is a catch-all. The intention is to select a nice sans-serif font on each platform.

Unfortunately, "Helvetica" can exist on Windows and Linux as well as Mac. Helvetica has been around as a typeface since 1957, and there are different versions of it around – by what route, or with what degree of intellectual property infringement, I do not know. There are also a fair number of variants that your computer might also consider, if they are installed.

On Linux, Helvetica was historically an X bitmap font (ugly, impractical things that are now effectively dead). These days it is generally an fontconfig alias for a free sans-serif font, but renders with iffy hinting and kerning, perhaps to conform to the original font's metrics (ie. it has been shoehorned into exactly the same space, so that printed publications don't come out wrong). I actually find this font quite uncomfortable to read.

On Windows, you may occasionally find Helvetica exists, perhaps even as the same font, installed on its own, or with some software suite, but if you do you'll find several browsers on Windows render fonts with Microsoft's ClearType renderer optimised for legibility, not the Mac's quality-optimised renderer, also used in Safari 3 on Windows. Microsoft own fonts have been tweaked to work well with ClearType – others may not. Linux is (as ever) more flexible: it's possible to configure the amount of hinting to use through fontconfig, although most users will keep their distribution's defaults.

Ultimately it's an impenetrable picture – you cannot be sure that the fonts you list will give anything like the browsing experience you were expecting. The same overall picture applies with serif fonts and monospace fonts.

The best solution (unless you want to try downloadable fonts, which I wouldn't recommend for body fonts) is to side-step the specifics of fonts entirely and delegate to the user/browser/operating system. There are three suitable aliases for font families: sans-serif, serif, and monospace. These will reliably give you a good font of that category. There are two other aliases, cursive and fantasy which are too poorly defined – you could get practically anything.

Is this really the only option? If you're prepared to go to the enormous lengths required, can you not pick a list of named fonts, test broadly and claim it works? Well, yes, if you test broadly enough you can get say 99.9% coverage. Unfortunately, that's not always good enough.

The topic of a site turns out to significantly affect the statistics of users that visit it. For example, a site about Linux will get more Linux hits. A site about using Photoshop will get most hits from people with Adobe Creative Suites installed, and that comes with fonts. So as a theme designer, what was 99%+ for you could be 90% for some of the people who use your theme.

So, in summary, stick to the safe fonts: sans-serif, serif and monospace. Fonts that are ubiquitious and designed for the screen are also quite safe – Arial and Verdana. You might be able to find some other safe places by consulting statistics if you are feeling creatively hemmed in. But please, don't make font assumptions.

In fact the only unusual thing was the omission of make-up to blend Aleks Krotoski's blush red nose into the rest of her face. I don't mean to be personally insulting to Krotoski – if my nose was coming out bright red on camera I'd want the production team to address it.

The story was woven into a history of the internet as told by "key players and pioneers" including Sir Tim, Youtube, Wikipedia and Arianna Huffington of frequently alt-med promoting rag HuffPo, thus neatly side-stepping the role of the millions of faceless bloggers and web users who pump content into the web and Web 2.0 sites and who are in truth responsible for what the web is today.

Actually, I say sidestepping – blogs were mentioned.

The world of blogging is going through a crisis. Of the more than 130 million blogs active since 2002, it's estimated that over 90% are now dormant.

Ok, a lot of people set up blogs and stop posting to them. But ignore that: what they've reversed here is the fact that there are 13 million active blogs on the web. That is a HUGE number. That means there is one active blog for every 130 Internet users.

Youtube in particular is noteworthy only for being the most popular video distribution site. As a site neither pioneering or unique, you wonder how their CEO's opinion could possibly be more valuable than that of it's more popular video bloggers. Incidentally, unlike many sites, such as Facebook, there's almost no drawback to switching to a competitor, such as Vimeo.

Jimmy Wales, founder of Wikipedia, on the other hand, is truly visionary. Nobody would have thought a wiki could scale to the size of an encyclopaedia and beyond without its quality suffering a lot more than Wikipedia's actually does. The result is the most useful site on the Internet outside of Google. Wales did not, of course, invent the wiki or prove the wiki concept itself.

But the main thing this programme gets wrong is simple definitions. The whole episode laments the fact that the internet was supposed to be democratic, but they claim it isn't because everyone uses Facebook, or Youtube, and sites like HuffPo get more traffic than your average blog. The word oligarchy was used.

Wrong. People can choose which websites to use or not use. Remember Myspace? Owned by News Corp, one of the world's biggest media companies? What happened to that? I suppose, as oligarchs, they must have decided for us that we weren't going to use it any more, right?

I won't bother with the rest of the series.

hi! <recipient's first name>! <link>

All of the messages were shown as sent via Facebook Mobile, which, to my knowledge, I have never used.

I did several things:

1. I posted on my Facebook wall advising people not to open these messages.
2. I reported the intrusion to Facebook.
3. I changed my Facebook password.
4. Replied manually to every message sent warning people not to click on the links.

Below is the reply from Facebook. I've not replied yet, but it's frustrating that Facebook have not listened to a word I've said.

Subject: Re: Messages or Posts Were Sent From My Account, and I Didn't Send Them

Hi,

We have detected suspicious activity on your Facebook account and have reset your password as a security precaution.

Er… I told you about it. You're replying to an e-mail which I sent you about it. Detected my arse.

It is possible that malicious software was downloaded to your computer or that your password was stolen by a phishing website designed to look like Facebook. Please carefully follow the steps provided:

1. Run Anti-Virus Software: If your computer has been infected with a virus or with malware, you will need to run anti-virus software to remove these harmful programs and keep your information secure.

For Microsoft
http://www.microsoft.com/protect/viruses/xp/av.mspx
http://www.microsoft.com/protect/computer/viruses/default.mspx

For Apple
http://support.apple.com/kb/HT1222

As I told you in my e-mail, I run Linux and it is up-to-date.

2. Reset Password: From the Account Settings page, you will need to create a new password. Be sure that you use a complex string of numbers, letters, and punctuation marks that is at least six characters in length. It should also be different from other passwords you use elsewhere on the internet. Here is your new login information:

<redacted>

As I told you in my e-mail, I have already changed my password. Changing it again and sending it to me in cleartext e-mail is actually making the security of my account worse.

3. Secure Email: Make sure that any email addresses associated with your account are secure, since anyone who can read your email can probably also access your Facebook account. If you believe someone has accessed one of your email accounts, you should change its password.

As I told you in my e-mail, I don't believe anyone has access to my e-mail.

4. Never Click Suspicious Links: It is possible that your friends could unknowingly send spam, viruses, or malware through Facebook if their accounts are infected. Do not click this material and do not run any .exe files on your computer without knowing what they are. Also, be sure to use the most current version of your browser as they contain important security warnings and protection features.

As I said in my e-mail, my operating system is Linux and it is up-to-date. I cannot run any .exe files without serious difficult. In practical terms, it is very unlikely to have been compromised.

5. Log in at Facebook.com: Make sure that when you access the site, you always log in from a legitimate Facebook page with the facebook.com domain. If something looks or feels suspicious, go directly to www.facebook.com to log in.

Please. If I want to visit Facebook I select it from the AwesomeBar. I don't even receive e-mails from Facebook any more because I've disabled them, so I'd spot a phishing attack a mile off.

6. Learn More: Please visit the following page for further information about Facebook security and information on reporting material http://www.facebook.com/security

Wow, practical.

Finally, if this did not resolve your issue, please revisit the Help Center to select the appropriate contact form and submit a new inquiry:

http://www.facebook.com/help/?ref=pf

So that you can ignore what I say all over again?

Thanks,

The Facebook Team

Thanks for nothing.

These e-mails include random links, and it's probably that the nature of the attack could be uncovered by finding out more about what these links contain. It seems very probable that the page you would see will try in some way to continue the attack. That is the definition of a worm: an attack that propagates itself over the network. I tried downloading the contents of a link with wget. It timed out.

Worms are not unknown on Facebook. As always, think very carefully before clicking on untrusted links, installing untrusted apps, and check carefully that the site you are entering your credentials into is the one you expect.

My thanks to Sammy and Marit for alerting me to the attack.

Twitter is usually described as a microblogging service, a term which is not really descriptive but slightly disingenuous. Users write 140-character tweets. They can select other users to follow, thus building a stream of tweets that, hopefully, matches your interests. They can reply to or mention other users. It's also possible to retweet or "RT" a tweet, distributing it to your own followers.

This misses the point. Twitter provides three main things: identity, a voice, and the ability to build channels from other users' voices.

Supporting this, it also provides numerous ways to find different voices to add into the mix, with searches, and links from other tweets, and trending topics. Unlike other social networks you are generally free to follow whomever seems interesting: your voice is public, your followers are not your friends but those interested in your tweets.

Your identity, tweets and channels can be used on third-party sites as well as Twitter, which means that Twitter can be used as a platform for other applications. Whereas Facebook provides a photo albums tool – like it or lump it – use whatever photo-sharing website you like with Twitter. There are several in widespread use. It's quite a democratic system. You can often log into third party websites with your Twitter identity, tying your actions there to your Twitter voice.

Twitter is more like IRC than blogs; the short tweet length demands snippets, ideas, jokes, links and – though it's not quite a 'real-time' as IRC – it's quite possible to conduct a conversation.

People do not tweet about every little thing they are doing. Such a Twitterer would not be interesting to follow. It's not just the latest fad; it's a platform for sharing news and interesting tidbits that has already broken major news stories, made and buried film releases, and on which is built a rich and growing collection of social tools that, unlike Facebook, compete with and improve upon one another. And you don't need to know people, because there are already thousands of people tweeting about exactly those things you are interested in. Follow them, reply to them… maybe you'll even make some new friends. When's the last time you did that purely on Facebook?

The best advice I can give to anyone who has heard the buzz about, but didn't "get" Twitter, is just to try it. Twitter is new, and people are constantly discovering new ways to use it. Tweet about what interests you. Follow people who interest you. If you do, you'll probably find Twitter interesting and engaging.

The moiré pattern of blurriness is an artifact – evidence of the fact that these "Look inside" thumbnails are caused by resizing already thumbnailed images – probably the thumbnail of the book cover without the "Look inside" banner. To avoid this on your sites, you need to build thumbnails from a sufficiently high-resolution image – ideally a high-resolution original. In practice, it can be faster and less memory-hungry to thumbnail from a medium-sized image, and this will generally not show visible artifacts. Of course, if you've already got a high-resolution image loaded into memory, you can side-step all of the quality issues by building all of the thumbnails you might need from it at once. Note also that you need to resize down enough to hide any JPEG compression artifacts.

To understand how the tell-tale moiré pattern comes about, let's imagine the source and destination pixel grids:

When we overlay them you can see the moiré pattern appearing.

Where the grid intersections are aligned, one source pixel maps fairly closely to a destination pixel, which makes that spot in the thumbnail crisp. But as you move away from those spots and the error builds up, the grid intersections disalign, and one source pixel is smeared over four destination pixels. That makes for a blurry spot.

I have discovered that Answers.com improves on this with a rather nifty hidden feature: if you double click on any word on the page it will immediately look that word up in Answers.com using AJAX!

This looks very innovative to me. Using the rich Javascript API to augment the browser's existing functionality is very pleasant, but here the product is a dictionary/reference site that is totally cross-linked! Poor old Wikipedia seems rather limited by comparison (though, to be fair, there are massive advantages to conventional links. This technique is not a replacement for that).

To get plugins, search Mycroft, which is fairly comprehensive for documentation resources. Where the documentation you want doesn't include a search engine, plugins can be found that search the documenation with Google.

Though little-known, it's extremely useful! A favourite trick is to double-click and drag to select words, then right-click and "Search current search provider for".

This word selection can show up an accessibility problem. Browsers and probably some search engines identify words by splitting the content on whitespace and block-level HTML tags – not on inline-level tags! This is sensible. If I write HyperText Markup Language (ie. highlighting initials in bold), I don't want the semantic content to be "H yper T ext M arkup L anguage"!

The accessibility problem is this. With CSS it's possible to accidentally write HTML that is neatly padded to look like words, but which doesn't tokenize (split up into words) properly. For two words to be considered separate you need to include semantic whitespace. Sites as big as Facebook and Twitter still make this mistake!

If your browser supports proper word selection (Internet Explorer's word-selection model is useless here), try double-clicking near formatting changes to check that your website is semantically correct.

Try it out! Can you detect the difference between these?

withoutsemanticwhitespace

with semantic whitespace

There are now quite a number of websites which allow free website thumbnails. While these services are pretty good, and I recommend using them, these services require a huge amount of bandwidth to load the websites and serve the thumbnails, a lot of CPU time to render the websites, and a lot of storage to store them all. This means they consume money and the companies running them place a variety of restrictions on what can be done with the thumbnails. Also you very frequently find thumbnails don't yet exist or no longer exist, and the thumbnail service serves up some advertising instead, which is bad for usability. Perversely, it's for the same infrequently visited sites that it's hardest to remember that thumbnails get purged quickest.

If Google or another large search engine entered this market they could make a fast and free service that would be self-supporting. They are the only people who are making vast amounts of money enhancing the web – because a better web drives more business through their main search engine.

However, in the absence of that, I wonder if we shouldn't turn to distributed technologies to make the business of understanding where a link takes you an innate part of web standards, rather than a bolt-on service controlled by a vendor.

You could imagine a web standard similar to the favicons system, where thumbnails of the website are available at standard sizes – say 128×128 or 256×256 – at /thumbnail128 and /thumbnail256, but this places the onus on the publisher to create the screenshots and keep them up to date. Even worse, it's not a great idea to trust the website themselves. Shock sites, porn sites or scam sites could benefit from misleading users into visiting a site.

One solution might be a distributed network for website thumbnails. A lot of research and development has been done in the area of DHTs particularly to improve the performance and decentralisation of peer-to-peer networks. A client could look up a URL in a DHT to obtain a URL for a thumbnail of that website.

There is also a way of generating thumbnails in a distributed manner: web browsers. There are so many web browsers visiting so many websites that if you could tap into only a tiny fraction of them – with, say, a Firefox extension that generates and uploads thumbnails using <canvas> (assuming you can work around the privacy implications) – you could get good coverage quickly. Because it piggy-backs onto the normal web-browsing experience, it uses very little extra bandwidth than what users were already using.