I have an AO3 account myself, simply because I have one fanfic I work on sporadically, and one friend who is sure he'll go to hell for reading here. (I like warmth, so I'm fine with a well-toasted afterlife myself.)
It's a highly contradictory site, and governs by committee. That, for me, is the "enough said" part right there.
For myself, I adore good solid concrit. I will never improve if I don't know where I need to improve.