Do comments raise the chances to win giveaways ?

Coincidence.

No.

yes.. you must spam the giveaway with "thank you" posts

Nope. However, active users are more likely to be noticed and invited to special groups. I myself have a couple of giveaway groups for people I like on forums.

Nope, but that usually means that they are on the forums often. Theres plenty of private giveaways here hidden or in a puzzle

Typically not, but it depends on the giveaway person. Some of them will reroll if you do not post a thank-you message.

Random is random.

People with more comments win more because they are usually here more often, join giveaway groups, enter private giveaways and so on. It's not actually because of the comments

You can't live if you don't win anything huh?

You're welcome to try this:

No.

Correlation doesn't mean causation.

The amount of comments affects rather indirectly on your winning, like some people described here.

No, but being active in the community does, you can encounter private giveaways.

Indirectly, yes.
Active users are more likely to find private giveaways and such.

other than that, no, comments won't raise your chance of winning a giveaway you've entered.

I noticed another thing. Those who post to point out the weirdest schemes, usually have very few comments. :D
Lots of comments usually just means that they are very present on the site = joining lots of giveaways, including private ones.

EDIT: don't worry, just keep joining and go on with your life. The wins will come! :)

Doesn't matter, it is just considered polite to leave a comment, though it is not necessary.

only special cheat comments like idkfa or hudsonsoft

No, i've won stuff without commenting. Has nothing to do with it.

Absolutely! That's why I am posting this!

thank you

Every vowel increases your chances of winning by approximately 0.001%, but each consonant reduces your chances by 0.01%.

Therefore, simply saying "Thanks" actually lowers your chances.

This has been proven, by the way. With science.

I stopped commenting becaue I stopped winning...or maybe I stopped winning because I stopped commenting. Who knows.

Obviously, just look at my profile! I have 4 wins and 494 (with this one) comments, when I'll reach 500 I'll win another game.
It works like this but people are greedy and want to keep the secret!