I just noticed today. I even found some new threads (within a month old only) have PR3 ! How come many dp threads can have PR? Do other forum sites have the same situation?
DP being one of the biggest webmaster forums on the net, that is no surprise. There could possibly be a number of inbound links to the threads you mention.
you can find more, here a 32 days old thread I found today which has PR3, but I believe it gained PR3 Dec/31/2008 around 10 days ago PR3 this time => http://forums.digitalpoint.com/showthread.php?t=1141639 mark it and lets see what happen next PR update. hope PR3=>PR4
for ppl like you to ask the question I would never of known, I'm guessing it's the same reason why some profiles have pr too it's DP!
Yh DP is one of the best forums and within a day the link is indexing also can see daily many times crawling DP. Can say DP the big in webmaster forum industry
New DP links are often indexed in under an hour. It's quite usual to see some threads with PR. Threads in DP have a lot of ways of getting linked from member's control panel's and so on.
This is called inner pages pagerank, Didn't you know that your websites pages can have pagerank as well? such as main site to have pr 4 and contact page to have pr 1 or 2 ? That's the same thing as here!