About the time of the recent server maintenance, (Jan. 13, 2012), I saw similar twice. When I went to reply to two threads, I got an error, did a Copy for later, Cancled out, and wow! the whole thread was gone. I thought that maybe a MOD had moved it, as in both cases, there could have been a question on appropriate forum, but could not find them. I checked the poster's profiles, and those two threads did not appear for either - do not know if THEY deleted the posts (odd that both would on the same day), or the posts just went to Byte-Heaven? In my cited cases, there are just too many unknown variables to determine if it was like what you observed, or just some easily explained similarities.