301 is an uri redirector. It allows you to create short links for long web addresses. Just submit a longish uri in the form at 301.sickos.org, and you receive a shorter handle therefor. This can be passed on the phone, on irc or wherever you want to use a tiny uri.
Some of you may be aware of the technique of banner grabbing to find out what software is running on a remote machine. It is done by reading out transmitted data that contains a product name and/or version, such as HTTP's "Server:" response header. Like virtually every content sent by a server, the server is totally free what to send, i.e. this can be easily faked by an HTTP server's admin, and is sometimes even done.
presentation on varnish cache
