No, I didn't delete it. It went down to -3 karma, which apparently hides it on the discussion page. That's how I'm assuming it works anyway, given that it reappeared as soon as it went back up to -2. Incidentally, it now seems to be attracting random cold fusion "enthusiasts" from the greater internet, which was not my intention.
The hide / not hide can be set individually by clicking Preferences next to one's name. I think you are seeing the result for the default settings - I changed mine a while ago and don't remember what the default is.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.