I discovered when I went to delete it that this posting had a dozen or so comment spams, but none of my other posts had any comment spam.
Why should this post be full of comment spam, but none of the others?
It doesn't seem to be one spammer who somehow found this URL. Or if it is, it's a spammer who contracts out spamming job, since the spam pointed to a bunch of different porn and Viagra sites.
One possible theory; someone linked to this post, to say "this thing that happened to me happened to luckylefty too", and once there's a link to a post, google is more likely to find it.