As the random words come from Altavista, I'm going to hazard a guess. Check your logs, and see if the user-agent is Webcollage. It's a Jamie Zawinski project which pumps evocative random terms into the return-more-results-than-any-other-engine-at-all-costs Altavista, and parses the resultant graphic files into (duh) a collage. http://www.jwz.org/webcollage/ tells ya what you need to know. (At first I found these odd, now I just filter 'em out.)
I seem to remember someone creating a script whereby you can search the SE of your choice with n random dictionary words (you choose "n", too).