I have set it to subscribe to threads I reply to, but not send any alerts. When I log in, the first thing I do is check my control panel, and I see all threads I've posted in that got new replies (I also sometimes subscribe without posting if I have nothing to say but want to follow it). Then I check, usually, New to Poly, General Discussion and Press and Media Coverage for thread that seem interesting to me. From time to time I check for new blogs (I'm subscribed to a bunch) and that's pretty much it.
I don't think you can ever follow everything, so you need to take your pick at some point