Someone in the Semux trading thread spoke about a snapshot based airdrop for Bitcoin holders. Is this true?
Yes, check the OP.
In the OP they say "BTC Giveaway". So it is not clear what they mean. Could also be a raffle.
I am pretty sure the dev said SEM will be given away to BTC holders and the snapshot has already been taken a while ago.
Yes, we will distribute a limited number of semux to BTC holders. The snapshot has been taken at block #480,000; participants need to sign with their private key to claim the rewards. The final ratio and amount cap per address will be announced on Dec 1, 2017.