I signed up for an ICO the other day and saw that they were giving away quite a lot of tokens for just signing up with Twitter and Telegram. How do they benefit from this? Do they just want more followers or do they want to get rid of tokens? Or is it maybe just a scam?
That's just a way of quick promotion of the forum's threads, socials and telegram.
If an experienced investor sees that there was an airdrop he understands that there is ~ 20-30% of real (interested) followers in the project. Others follow because of airdrop's task.