Grargar: I think it's a simple typo, just like using "then" instead of "than". :P
It also doesn't help that it's prohibited to edit your posts in a mafia game, even for simple typos.
At least, that's what I understand, as a non-native speaker.
mrkgnao: I believe these are just typos for "than". The mafia games (from which you bring the examples) are especially notorious for having typos because it is disallowed to edit past posts, leaving no recourse for hiding past indiscretions.
EDIT: Grargar has already made the same point.
I'm aware of the "no editing" rule, I was just wondering if these were something more than mere typos, because I vaguely recall seeing this also in a couple of other posts of yours, outside that thread. And with you being a novelist... well, you get my drift.
Thanks everyone for clearing it up for me, had started to worry my English was not up to date.