About three weeks ago I moved some web pages and set up a new more centralized page, pointing to various new things under a single directory. As a result some links returned in Google search no longer exist.
Google's web crawler can be monitored using their webmaster tools (which I highly recommend).
Today is August 13th. Google has not indexed my pages since July 8th. This is in spite of there existing at least four regularly updated blogs containing references to my pages, posts in USENET news groups, my having brand new pages on the past two Googlebot scans, and my entering the new page here:
I realize Googlebot has a lot on its plate, but it's very frustrating watching days go by and knowing that links to no place are turning up as high as the first and second pages of search results. I light of how I know it would be abused if Google offered some way to request a rescan more directly, there's nothing to do but wait.
The Microsoft search engine and Yahoo have already updated themselves weeks ago. Yahoo in particular seems to come through quite frequently.