keyplyr - 7:52 am on May 23, 2006 (gmt 0)
I haven't a clue to why they do it, just a suspicion that it plays into the scraper scenario. Example:
63.148.99.*** - - [22/May/2006:15:18:26 -0700] "GET /%26y%3D029700D88CA97D40%26i%3D41%26c%3D2699%26q%3D02%5ESSHPM
EOPTK1IPG&s=175&t=&m=407BD303&x=0164DE6A9CD3A7EA HTTP/1.1" 404 1980 "http://www.some-scraper-directory.com" "Mozilla/4.0 (compatible; MSIE 6.1; Windows XP)"
Got a few of these today. I've seen several variations, but on each occasion when I back-track to either the referrer URL or the IP address, there's one of these scraper directories at the other end.