I have to say that it's interesting that you so quickly found that a reference to your theme had made its way on to HN, and on this particular thread. Unless I am missing something obvious?
He has been using HN over 900 days, and this is on the front page -- it's quite possible he simply saw the article and comments just like you and I did.
Sure it's possible. But, given that he hadn't commented or submitted on HN in 20+ days 'til now, it just seemed unlikely that he's currently actively delving into submissions/comments to the extent that he'd catch this so quickly.
So, I just found it not so much an "Aha! Busted!" moment, as much as it was noteworthy.
I made an Octopress theme a long time ago, and it looks like someone forked/used that theme to make their own theme. Source of that specific Feedburner tag is here: https://github.com/eturk/ethan-archive/tree/55a01aaa03398a57...
Whoever first forked it probably just commented out, and then someone used that and so on.