Okay, I know for a fact that I posted looking for the name and author of this alternative history story with the Aztecs in it on whatwasthatbook several few months ago, and it was the only book-related LJ community I had ever joined until less than a month ago. So I searched though the entire thing all the way back to September before giving up. Posted about it again. Took forever for them to approve it, when they finally did one of the mods posted that they searched the entire archives as well and could only find one other post by me (which I had seen too) about a completely different book.
I'm not just imagining this, though. I remember posting it, I remember seeing it there, and I even remember some of the suggestions made. One I immediately recognized so completely that I knew before checking it out that it definitely was not the one. Another sounded familiar like it might be the one I was looking for, but I would have to check it out at the library to be sure.
The way I figure, it's either been deleted for some reason, or I am remembering things before they even happened, in sharp detail. And if that's the case, I'm going to start waiting. The lottery numbers for next week should be coming any time now. :-)