I belonged to another forum before this one, but I'm not going to recommend it. People turned petty & mean, the moderators acted like they were MDs or something, and if you said anything that they didn't believe was true, they stopped responding at all to any of your legitimate posts and nearly all of the forum did too. This one I've found to be most active.

I do belong to an ED recovery forum, but it's slowed down a lot; I don't post there much any more.

And it is nice that this PC has lots of mental health forums for other issues that can accompany bipolar, like anxiety/panic, PTSD, eating disorders, etc.