I wouldn't get too excited about all of this. It looks like it's still updating anyways. Do yourself a favour and check your allinanchor: instead of the google PR. It means more =) Hexed
It's not been propagated across all of the datacentres yet. Don expect it to settle until tomorrow at the earliest
The toolbar hasn't been updated with the new PR yet. It's changing through the data centers, and could update soonish. We don't know if the PR showing on these data centers will be the toolbar PR - only time will tell. I don't think it's very professional though for people to laugh at others peoples mis fortunes - you don't know when its going to happen to you.
I've seen sites reduce to PR0 for bad linking, i.e. siteA.com and siteB.co.uk same company, both sites on the same IP address, and one of the sites was dumped out of Google and given PR0. There could be hundreds of other reasons though.
Running an error page like sitepoint.com/forums/aslfd.php through a great server headers checker shows a 301 back to sitepoint.com/forums/, that might be the cause. They also have a 302 redirect from non-www to the www version of the site...
Just found this thread in a search. 1/2 weeks later and I get PR0 on: http://www.sitepoint.com/forums/ Looks like the rumour of it going to 0 was true then?
SP started charging money per thread... Yet, I find it amazing that DP gets much more traffic, and has much more activity and more expensive servers than SP, and does not charge anything.