Yahoo! Slurp is Yahoo's web-indexing robot.Google and other search engines use them.
Their job is to find new web pages and put them in search results.
I don`t know why Yahoo`s spider is so prevalent.Everybody uses google.
Spammers also use Spiderbots to harvest email addresses from webpages
If a Yahoo spider mates with a Google spider,they produce Goohoo spiders.(That bits not true)