There's a line from the first Matrix movie, the only really good one out of the trilogy, where Morpheus says earnestly to Neo ... fate, it seems, is not without a sense of irony. It's time to add a corollary to this quote, along the lines of web geeks, it seems, are not without a sense of humour.

Last year, it was the web geeks who run the web servers for Yelp and Last.fm sticking Asimov's Three Laws of Robotics into their respective site's robots.txt file. Sadly, it looks like Yelp's robots.txt is now unfunny and businesslike, but Last.fm's subversion of this file is still there.

I'm not talking about vaguely human looking machines here, the sort that crop up in Forbidden Planet and Lost In Space, waving their metal arms and saying things like "Danger Will Robinson". What I'm talking about is a small file called robots.txt.

If you run your own web server you probably have one of these. It tells the web robots sent out by the search engines, such as Google, Yahoo! and Bing, what pages on your web site should and shouldn't be indexed and searchable. This doesn't mean that those pages can't be viewed, just that they shouldn't be able to be searched for.

Most of the time, a web site's robots.txt file contains stuff that is only of interest to the owner of the site and to people who specialise in getting the content of your web site to figure prominently in search engines. But sometimes, if you're willing to poke around a bit, they contain hidden gems, like a job advert for one of those aforementioned web search specialists, hidden in the UK Daily Mail's robots.txt file.