If I leave, not only do I lose the ability to participate in those conversations in a significant way - I lose awareness that they're even happening. The newspaper (what's left of it) certainly doesn't cover them. I have many friends who I see on a regular basis in person, but we don't always talk about all of them. And when we do, it's often inspired by conversations that were already happening on Facebook and a continuation of the conversations happening there.
We need a good replacement for this piece of it. Having an accessible, local town square where all the local activists, citizens, and officials can interact and dialog about local issues is really invaluable.