I checked out Sermo many years ago and didn't like it. At the time, my impression was that any decent conversation was nearly drowned out by stuff I just didn't care to read. Republican politics, as described above, as well as one guy from another specialty who seemed to take it as his personal mission to spam the psychiatry forum calling psychiatrists quacks.
Again, it's been many years since I've been there, but at least back then SDN was/is a much nicer place.