Maybe it's because the important things have started, and moved to real life, outside of the LW website. There are people writing and publishing papers on Friendly AI, there are people researching and teaching rationality exercises; there are meetups in many countries. -- Although, if this is true, I would expect more reports here about what happens in the real life. (Remember the fundamental rule of bureaucracy: If it ain't documented, it didn't happen.)

Anyway, this is only a guess; it would be interesting to really know what's happening...