dstiles - 7:26 pm on Jun 20, 2010 (gmt 0)
If the IP is a bot IP then it's yahoo - I doubt anyone could get an exploit onto it who wasn't yahoo. If it's not a bot IP it is possible that anyone could use it: there are a lot of yahoo proxies and access lines that anyone can use. Same with google and MS.
Some tests may be to see if a site has an open ecommerce point of some kind (or even a virus) but I think slurpconfirm404 is just that: to confirm what action a site is taking when faced with a missing page situation.
Some of my sites always redirect to the home page. Others redirect if a browser is detected (keep visitors on the site) but return a 404 if it's a bot (to please google, really). It's probably that kind of thing yahoo is trying to determine, although what they would do with the info is open to question.
I agree yahoo is the most agressive bot at the moment - always has been, I think. More than MS and Yandex. Far more than google normally crawls and at the moment almost infinitely more - google has almost stopped crawling my sites for the past few weeks: even yellow pages crawls more!