Bass47: I'm really sorry but if you already own the game (for the PC), you can't.
te_lanus: I Think I wrote wrong, as my real meaning didn't come thru, sorry. What I meant is anyone can enter, thus when the GA ends just make certain the winner doesn't own it already.
This is a good advice. I also own both items from the Limited Edition and can also enter that giveaway as if I don't have that edition or the base game. As many more games on SteamGifts, you may have partially or complete editions and still enter for those, unless the users of the site manually hide those giveaways. But still many users don't do that or don't know how to do that and still enter in those, by mistake or knowingly to take advantage of this, and have won (and then banned or suspended from the site or groups when discovered :P).
As an example, one common giveaway that can be won multiple times is
Tropico 4 Collector's Bundle.
