My apologies if you're seeing any of my old posts reappear as if freshly published. Comment spam has gotten so bad on some posts that I'm resorting to disabling comments completely. I think this triggers a republish by Community Server (at least, I have to click the "Publish" button), which some blog readers will then interpret as a new post.

If I was sufficiently interested I'd see if there's a direct correlation between the spam-attractiveness of a blog post and its Google PageRank...