Your idea is fine, but consider a situation. A person very muchly wants a game (like for me Papo & Yo) and they might be unable to buy it. Lets say you happen to have a copy of that game. You want to give it away. So, you just go ahead and post it here. A different third person comes along (not saying they are a bot) and they see the time 'just posted', they are of course ninjahs, and they don't have the time to look up the title on Google or Steam or Desura. They know that in doing so, they might lose the free game. So they say,what the heck, and post it in their Steam/Desura activation screen. And Lo and Behold! they get it! But then they go to the respective platform and see its a genre they completely dislike, and probably wont even look at twice (I'm sorry to say this has happened to me), so whats the gain? Sure, you get that warm feeling inside that you gave, but what about the person who wanted it most? I know its completely possible that he/she might not even be online at that time (saying they are members here) but still, at the 10-30% chance that they might, well, I see every reason to follow MAHAYO.
I'm not criticizing your generosity, what you're doing is awesome. But there are ways to make it awesom-er.