Ask HN: Why did my post disappear from the front page?

Last night I submitted a blog post* to HN. It got a dozen upvotes, sat on the front page for a couple minutes, and then promptly disappeared. It wasn't on the front page, or the second page, or the third or the fourth or the fifth. It was just GONE, from everywhere except "new."

Why did this happen? I've speculated that, because a few friends upvoted me, it got caught in the spam filter. (But seriously, it was only two.) Is that it? Or was there something else?

At first I was upset--it was something that I genuinely wanted the HN community to see--but now I'm mostly just curious.

*This question isn't a ploy to share the post, but for the curious here it is: http://news.ycombinator.com/item?id=3851373