I played on play dip from Dec 08 into Fall 09. It doesn't look any different now, except that it has a point and click interface, which is the only real advantage that I can see.
Compared to this site, I hated the dull community. People did not communicate much. The forum here may be unorganized, but in this case, chaos brings the community together by keeping a bunch of great people in constant awareness of all the conversations. Even the rude ones can be funny, and eventually they get tired of being rude all the time.
The skill of the people on that site was also below the players here, but maybe that has changed. Here at least the point system keeps you playing against your skill level. And the Ghost Rating is a better ranking system.
There were common site problems same as here, but they would last up to a weak sometimes on playdip.
I even preferred World Leaders (now Conquest of Nations) which has had point and click interface and a few good variants (Youngstown, Colonial, and a Greece map) for two years. It also looks better than playdip.
Webdip still has the more skilled players and an amazing community though, and that's what kept me here.