We have a site which, for SERP optimization reasons, years ago was broken into about 2500 subdomains. In google, this technique still works quite nicely. Inktomi, however, banned the site (every page) about 2 years ago. With the impending yahoo switch it has finally been decided to reduce the subdomains to under 500. We were told by positiontech that 500 is the magic number for ink subdomains. After much to do, we've concocted a scheme for mass 302 redirects. The question here is, after seeing *.domainname.com redirects- will slurp realize that the subdomain no longer exists? Or will it believe that the page it's spidering has moved? If so, how do I let spiders no that a subdomain no longer exists?
A 302 means the info resides only temporarily at the other location. If you don't plan to go back to 2500 subdomains, then I recommend you use 301's (move permanently) instead. You may see a time lag from when Google drops your old pages until it picks up the new ones but your pagerank and SERPs should be restored back. The 301's will tell Slurp those subdomains don't exist anymore.