Ah I understand.. you assumed it meant that anyone who comes to the site can get it. I suppose that could be confusing. We use the same term "giveaway" sometimes when we really mean that we have some copies to give away for free, but not everyone will get one.
It brings up an interesting issue in terms of words though -- because "raffle" and "lottery" are not really appropriate -- they usually imply to most listeners that one has to PAY to have a chance, and this is not like that. And a contest implies that the "winner(s)" will be chosen based on some criteria, rather than randomly.
So for the wordsmiths.. is there a term would you use to identify an event where things were being given away for free but only a few people were going to be chosen randomly to receive them?
I think in general, i've used "giveaway" for this purpose.. and *not* used it when there is an unlimited supply of something.. in the case of an unlimited supply i think one is usually more explicit and says something like "we have a free X for everyone who stops by".