Why is the Motion forum so dead?

Is it because there are not many users out there or everybody knows how to use it... or is everybody using AE?

There are a lot of other Motion forums that get a lot more activity - e.g., Apple's forum.

Because the LAFCPUG is know as a "Final Cut Pro User's Group". It is not high up on the "Motion User's Group" list. People generally go to Graphics / Compositing / Animation sites for that or Motion-specific sites like mark mentioned.

Motion use has fallen off greatly anyway from what I have witnessed in the Post Production community in my neck of the woods...

When life gives you dilemmas...make dilemmanade.