The Welcome subforum has quite a large amount of threads belonging to now-unregistered users, so it's a lot more than just a few.
EDIT: Anyhow. The point was that I'm still not sure as to why one would delete accounts with a non-zero amount of posts on them, so I was asking to see whether it was done intentionally or not. It is of course none of my business, but seeing as one of my RP accounts were deleted plus the accounts of a heap of relatively recent newcomers I'd rather ask just in case.