Contributing increasing win chance?

No.

It's Universe.

Nope. Everyone has an equal chance of winning. So it's just karma in your case :P

Justice? I think you mean karma. And no, it's pure chance. The contributor system does give you better odds at winning, though. If you're a contributor anyway.

Contributor giveaways are sort of like enforced karma; if you give you get a better chance to receive. I didn't win anything for months and this weekend I've won 3 contributor giveaways. Awesomesauce.

Contributing increases the chance of everyone, because there are more giveaways to win. :)

If contributors are entering contributor only giveaways, then their chances of winning are dramatically increased. (By the nature of having less people in the giveaway, say 100 people instead of 1200.)

If they only entered the public giveaways, their chances would be the same as non-contributors.

Well, I gave 4 Games away, still no dice. So no, has nothing to do with it :P.

It does, especially when contributing Fortix.

so... ther isn't anything that can increase the chances of wining

Gifting doesn't mean winning, you were just lucky.

its karma.