I think you are kidding yourselves thinking that there are significant communities discussing Bitcoin outside of this forum.
You're kidding right?
As a random anecdote even the dutch forum community "fok" has a significant number of people discussing bitcoin for some time. There are quite a few IRC channels discussing bitcoin as well.
And there are many local communities in different countries meeting up and working on BTC related projects.
Of course startups advertise on this forum, that makes business sense. That doesn't mean they are born on it.
I like these forums but don't flatter yourself into thinking you're everyone that cares about Bitcoin on earth.
Also, who uses the foundation forums? Is it active? Is there good discussion?
Just curious.
It's really inactive. There is a post once in a while. But usually if there is a post it's mindful. It's quite the polar opposite of here