Quote - I've been here for a long time and just recently noticed chat because it's right there on the main page now instead of hunting for it.  I use Hangout+ instead anyway for showing people how to do 3D stuff.

Hangout+? hmmm. I tried googling that, is it like a client side app or an irc chat room?

The best way to advertise is with a little bit of sex appeal which renderosity does already. If you put a render of a nicely rendered, attractive V4 pointing at the "JOIN CHAT NOW", they could get more people to join chat.