It appears PPBB will not close down.  The folks on that board are discussing ways right now to modernize the software and provide a more dependable funding source.  It has been a very active board (I would guess a couple of hundred posts a day - maybe more).  Admittedly, because of its format, it requires more than the occasional visit to "get it".   It is more socially oriented than technical - although there are certainly technical issues discussed "ad nauseum".  It has also spawned a number of annual or more frequent events around the country - such as the Blue Ridge Boxster Summit.   For those of us addicted to it, it would be a great loss.
Lawdevil Mike