Why my estimated wins are positive?

What do you think it means?

What would you expect it to be, -1?

It means that SteamGifts is really really optimistic that you are going to win because of your horrible bad luck to date.

http://lmgtfy.com/?q=what+is+estimated+wins

...

i estimate that you are not very old... continue your studies @ school and you will now what "estimated wins" means and you will know why its not negative. do we have a deal?

Your estimated wins is the statistical number of wins you can expect to have won, on average, given your giveaway entries so far. Since you've only entered a small number of giveaways, all public with a large number of people in them, your estimated wins is fairly low; it's not likely that you would have won anything yet. And, indeed, you haven't.

simply put , once it reached 1.0, you should of already won atleast 1 giveaway

Your account has a bug, that should be negative.