My site, www.2005calendar.com was ranked #2 for the keywords: 2006 calendar. It was mostly # 2 for a couple of months but went up and down between there and #8. It was being crawled by Google nearly every day. At the October update it went to every 13 days for all my sites. At the last Google update in October it disappeared. It came back to #2 for a few hours, (based on a visitors spike) bounced around between 20 and 300 for a few days, and the disappeared completely. I know I lost a PR7 link around the 1st of October. I have replaced it with 5 PR7 links, all on different IP addresses. I am still in the top 3 on MSN: I was #1 but changed the title and went to # 3. That had no impact on Google. I experiemented with a blog for a couple of months. The blog is at http://www.calendar6.blogspot.com/. The #2 position solidified right after I added an RSS feed on My Yahoo to the blog. I have now removed the RSS and deleted a lot of links from the blog. Google shows 66 back links and MSN 1600+. I have added links a few at a time from various sources. Anyone have any thoughts?
My site did the same thing, dropped down 9800 in the search results after a week google bumped me back up 3 pages higher than I was. Now I'm in the 4th page on my main keywords. So don't worry It'll probably be okay in a few days.
This PageRank stuff and Google Indexing is very complex and at best a guess in my opinion. However, I've seen the same thing. Doesn't Google sometimes reset their Indexes. I think they do because every so often my sites have to "work" their way back to the topic of certain Google searches.