I guess a year ago we were slightly ahead in our timing, or my post was too long, or (probably) I didn't emphasize Eric Ries and Venture Hacks enough...
http://hnpickup.appspot.com/hnpickup_ratio_visual_analysis.p...
More to come. Probably, this week I will get around publishing something on the "karma growth effect".
BTW, I've sent an email to "help@leanpub.com" about latex math support. So far I haven't heard back.
The short answer is that we don't support it. We could if we were just using LaTeX => PDF (which we do), but then things would blow up when doing epub and mobi.
I'll take this as another vote for the feature, though :).