The big hit is Danganronpa, which has received almost 18,000 posts. Free and Rozen Maiden are well behind at around 11,000. And Watamote is just behind that at ~10,000.
A surprise to me is Kin-iro Mosaic. At about 8000 posts, it leads the middle of the pack, followed by Love Lab (~7000). And we go down from there: Fate/kaleid liner, Gatchaman Crowds.... A fuller list follows.
The list includes only new shows that are not just continuations (as far as 2channel is concerned) of earlier seasons. Symphogear seems to be plowing through the posts, for example, but I don't know where the posts for this season start, so it's hard to compare. Same for Monogatari.
The numbers represent which number of thousand-post threads the show is now on:
|Rozen Maiden 2013||11|
|Inu to Hasami||4|
|Kami-sama no Inai Nichiyoubi||3|
|Kimi no Iru Machi||2|
My own favorites so far include Monogatari Series, Gatchaman Crowds, Genshiken Nidaime, Kami-sama no Inai Nichiyoubi, Love Lab, Kin-iro Mosaic, Kimi no Iru Machi, Rozen Maiden, and Uchouten Kazoku.
Danganronpa and Watamote may be good, but I find them too depressing to watch. Silver Spoon hasn't captivated me yet. Same for Free: I can appreciate the look, but the characters don't reach me.