Sometime a long, long time ago, I let in a trackback to a porn site on some old post. I think this was before I had moderation on.
In any event, a couple of months ago, after turning moderation back on, I noticed I was getting a ton of 'pingtrack' (Subtext language) comments to moderate. A few hundred a day. Tied to the one post that one had slipped by into.
After a few days of deleting them (more or less automatically), I turned off trackback/pingback support entirely. Nothing more to moderate appeared in the Admin.
Well, I was looking at some reports that indicated my traffic had increased 400% (at least) recently. Since I've never ever had anything interesting on my blog, and certainly nothing recently, I took a look at the raw logs.
They keep trying. The fact that the links never appear seems to have increased their activity immensely.
I guess they hope that they are all stacked up and so when I turn trackbacks back on, tens of thousands of links will appear. Dumb.
I know one standard approach is to turn off comments after a post's entry date after a certain period of time, but one thing I find personally annoying is discovering some blog post from some time ago that I've never seen till now, and been unable to respond since too much time had passed.
Still, I worry about the poor slaves in Slovakia (did trace one such spam farm to there) who are continually adding spam to (mostly) porn sites (though every once in a while they would try to slip in a trackback to Iowa Men's Soccer or something similarly benign), and they don't even get the joy of knowing I'm manually deleting them.
Idiots.