A good mind to write a letter

The comments left on ancient blog posts here tend to be on the furious end of the spectrum. What inspires someone to leave a comment on a post from ages ago? Are they hoping someone will use the same search terms they did and join the snail's-pace 'conversation'? Regardless, I bring this up because today was the best one yet: a trollish commenter accuses me of - drumroll please - having never been to New York.