runboy - 10:50 am on Jul 30, 2005 (gmt 0)

"Google's automated response to me said that sites fall out of the index all the time.
"Our spiders regularly crawl the web to rebuild our index, but keeping tabs on eight billion pages is tough work, and they may miss a few". They go on to say that if your site is well-linked it should be picked back up.
"

I can believe this to be true with sites that have few incomming links, but I have never seen it happen to any of my sites that are heavily linked.