Can anyone shed some light on EXACTLY what happens to Google PR after a domain expires?

Does the PR stay with the domain if it's immediately re-activated?

Does the content on the domain matter after expiration for PR to remain?

If PR goes away - does it happen instantaneously?

Are there any other 'special circumstances' under which PR will or will not remain with an expired domain?

Thanks for any info on this!

Google has an expired domain filter. They are watching for domains to expire, and then automatically applying a filter.

Webmaster-Forum.net used to be owned by a German webmaster-forum. It had no PR. It expired, and I bought it shortly after (a week or so). I got the domain up to PR7 the first month. It was at PR7 for 2 months, I believe, and then it got hit with the "filter", and dropped to PR1. It did not show up in the SERP's at all.

I mentioned this on WMW, and GoogleGuy PM'ed me. We then exchanged a couple emails, and it he looked into it and discovered that Google had hit it with the expired domain filter.

He fixed it, and it went back up.

But most of the time, Google doesn't fix it. We bought Las-Vegas-Realty.com shortly after it expired. We gave it thousands of links. It should have been PR7. But it remained PR0, and didn't show up in the SERP's at all even after several months. So we finally just went with another domain, which was immediately included and got good PR.

I'd stay away from expired domains. They can be messy.