Andrey forwarded me a link to last.fm robots.txt file, which, as many other robots.txt files, forbids search engine bots to access certain areas of the site. This one however does a little bit of more. For machines, it serves as the reminder of Three Rules of Robotics by Isaac Asimov. For humans, it provides a tiny bit of geek humor. Here is a screenshot, in case it disappears over time.