Is there an online community that is dedicated solely to discussing friendly AI research topics?

None that would be active and of a high quality. SL4 is probably the closest, but these days it's kinda quiet and the discussions aren't very good. Part of the problem seems to be that a community dedicated purely to FAI draws too many cranks. Now, even if you had active moderation, it's often pretty hard for people in general to come up with good, original questions and topics of FAI. SL4 is dead partly because the people there are tired of basically rehashing the same topics over and over. It seems like having FAI discussion on the side of an established rationalist community is a good idea, both to drive out the cranks and to have other kinds of discussion going on that isn't directly relevant to FAI might still contribute to an understanding of the topic indirectly.