Regards comments, coming here from the Facebook posting... originally went to the blog, but saw no immediate reference there. Incidentally, posting here required me to create a login, so maybe that's why people don't bother? Anyway.
I'm speaking here as someone who also writes and posts up a math series, and I suspect the problem is twofold...
1) Finding the Audience. Which would, it seems to me, be mostly teachers and students of mathematics, more than comic readers in general. Just a guess - anyone else out there is welcome to correct me. Meaning that the more generic people who stumble upon (x, why?) might not fully get the joke, and even if they do, they may not want to comment on that fact. (When did math become this social pariah anyway?) As to the teachers and students, they have to come across it first. I found (x, why?) because I was actively searching a couple years ago when I was starting out myself, and even then it was a link off the Spiked Math site. (I prefer yours, by the way.
Then the other issue is:
2) The Time Factor. Teachers and students are pretty busy a lot of the time... which either means scanning, having a chuckle, and moving on, or marathoning updates on a weekend, such that you're too busy reading to comment or figure a comment five days after the fact is a bit redundant. (Again out there, correct me if I'm wrong!) I know I only tend to comment if something strikes me just right. (I also figure that if I comment on a couple, then don't on the next couple, the person might feel that the next couple weren't as good, even if they were, so not commenting avoids the whole problem - by creating a different problem. Logic? Bah.)
My own series (Taylor's Polynomials, mathtans.ca, for anyone out there who's curious) has the third problem of a continuing storyline, so while each entry is meant to stand alone, the issue of context (and, well, text) is probably a turn off too. As a result, I get 10-20 hits. Total. Usually up to a dozen upon first publishing, then a few entries creep higher, maybe. So I at least TELL myself those are the reasons why I (and perhaps countless others) have little to no feedback. That keeps me going. (Also, I think there's a German blog site following me. So yeah. The internet is bizarre.)
In summary, yes, I do follow along with (x, why?), and I am lousy at commenting. (I am slightly better at retweeting...) I found a recent one about pencils particularly amusing (just looked it up - Number Two from February 2013), wish you all the best on your voice acting prospects, and if memory serves, you even had comics linked in at a math website (mathfail?) -- so well done! Assume the lack of remarks means you are doing such a good job that any improvements must simply come from within. Or whatever else keeps you going, because we need more people like you making math fun.