setzer - 5:04 am on Oct 20, 2010 (gmt 0)
My site dropped from a strong PR5 to PR3 last week. Unsure what caused it. We have around 200K inbound links. None of these links were bought, nor do we engage in link sharing.
Anyway.. I'm not complaining since search traffic is up about 20% since the drop in PR. Go figure.
We did, however, buy out a competitor recently (about 3 months ago) and 301'd all pages to our site. Perhaps this caused it. They had a PR3. Still strange though..