Has Steamgifts ever caused you to buy a game ?

Yes. To giveaway.

Yes. I won a Serious Sam HD 2nd Episode, and I bought the 1st episode because of the gift.

Yes. 8 times.

Yep, I kept entering for Magicka, and never won. I ended up buying the four pack for me and 3 friends.

I assume if I didn't use Steamgifts I might never have known about IndieRoyale and IndieGala so do those count? I can't think of anything else, except maybe Cthulhu Saves the World, I think I might have found out about it here.

I always check out a game on steam to see if it's good enough to enter a goveaway for. So yeah this site is free advertising for games.

Never for myself, no.

a) to buy a game to give away, and
b) to buy copies of a game I won for my friends, and
c) to find some of the more obscure indie bundles

Yes... through reading the forums and getting a heads-up on great deals.

So basically, steam gifts awakes the spirit of awesomeness in people. causing them to giveaway games?

yep!

I didn't know about Half Life: Source before I joined

Yes.

Sometimes I would feel eager to giveaway games

Only if I find a hidden gem