Either I promoted this and then forgot I'd done so, or someone else promoted it - of course I was planning to promote it, but I thought I'd planned to do so on Tuesday after the SIAIers currently running a Minicamp had a chance to respond, since I expected most RSS subscribers to the Promoted feed to read comments only once (this is the same reason I wait a while before promoting e.g. monthly quotes posts). On the other hand, I certainly did upvote it the moment I saw it.