Every time you fetch a web page, your browser sends a special User-Agent string to the server telling it what software it's running. It's defined in RFC 2616:
This is for statistical purposes, the tracing of protocol violations, and automated recognition of user agents for the sake of tailoring responses to avoid particular user agent limitations.
Fast forward to 2009, and here's the User-Agent string you get from Google's fancy new Chrome browser:
Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US) AppleWebKit/525.19 (KHTML, like Gecko) Chrome/ Safari/525.19
It's like a browser salad! But the Google guys aren't doing anything wrong, this boneheadedness has to be there in order to satisfy the "automated recognition" part of the spec. Chrome's just a little ol' chameleon.
  2009-03-19 19:35 Z