Since GMail collects all replies to emails into a thread, and indicates how much replies have been made it’s pretty easy to see which posts have gotten replies, and which haven not. If a post doesn’t have a subject that interests you at first glance, and it has shifted down to the bottom of your inbox without any replies, you can assume it’s pretty safe to skip it and simply mark it as read.
Even if you’ve marked something as read, and a reply comes in anyway, it’ll pop back up and get your attention after all. So there’s no need to worry about missing too much. That way you’re using other people as your shit filter, without them even knowing about it. Sweet! Don’t forget to take a peek at the ones with subjects that might trigger your fancy though.
Someone has to be making that first reply remember, and that person might be you.