As Lynne says, I think forums in general have slowed a bit since the mid/late 2000's.
Its fair (and accurate) to say vb.org is not as busy as the same period in 2008.
However, we get well over 2,000 people log in every day, 11-13 thousand posts per month, and there were 81 new releases in the last 30 days - so any talk of a demise is just a bit premature I think.