PR 4 for a forum is a great PR...Plus, it isn't that important at all, knowledge and different interactions are this forum's asset.
I think it's mainly because they don't use the 'nofollow' attribute on outbound links e.g. peoples signature etc.
The public PR in the toolbar is not the same as the internal PR. Most likely DP has a much higher internal PR. Some years ago it was obvious that the number of hits from Google increased or descreased depending on the PR shown in toolbar. This is no longer the case. It seems Google is updating internal PR every week. Public PR is just to keep us all talking about them.
Does that really matter? Think about the amount of traffic it gets, And quality of knowledge and information we gain from here, So PR really doesn't matter to me, No matter if its DP or my own sites.
Pagerank isn't everything. Whatever DP is doing, they couldn't be doing it better! Thousands of uniques per day! Wow Oranges! You and I think a like! Posted the same comment at the exact same time. lol
I think for those who wants to build links using DP, they will get easily disappointed that it is only PR4...but for those who wants to build relationships online with people here, learn more about online stuffs, PR does not really matter that much.
I don't think it's down to that and we can only speculate anyway. ...the Meebo forum is PR8 and they are dofollow.
PR doesn't really matter for DP anyways they appear at the top for the weirdest things anyways. For Example : the hottest girl in the world
I see in www.seopenalty.com what http://forums.digitalpoint.com have a VERY HIGH PENALTY 10 - 11 points, maybe is that
PR is needed for traffic when you have traffic you don't need page rank so it's not a problem for them i guess
Official pagerank and traffic from Google is no longer the same thing. Traffic from Google depend on other things. Maybe Google have it's own internal PR...I don't know...but it is no longer as before when PR and traffic from Google followed eachother closely.