Yep, fairly new feature from Steam. If you scroll down a little ways on main Steam game pages/click upper-left window in many cases on steam giveaways where graphic of game is, and below friends who own/want game, where it has statistics in the normally dark blueish interface over there, (single player and achievements in the case of this one) it'll say "Steam is learning about this game" in a greyed box, and it's kind of for lesser known games for them to gather more info on I presume. I have had some issues with both joining before (earlier on before I was aware of the feature being so prevalent with games) and also having other people join a few of my own giveaways with this. Too annoying to check every single game for it, and mods are quick on rerolls, but still if I do mention it, I get pretty livid - well... only "steamgifts" version of livid - about winner not reading my note in description.

It's not nearly as messed up as if I put in huge letters to check if it's obviously a dlc/goty style as you mention above... and end up seeing a winner that owns something... I kinda tend to blacklist that behavior, but it still kinda sucks. I don't really fault people near as harshly on the former case though... Maybe I am too evil or intolerant with the dlc thing, but I do get very upset on those. Want things to run smooth as possible for everyone on steamgifts, and not clog up mod tickets if possible. I'm sure their very thankless job is hard enough as is!

It's worth a look either if you're joining or giving them out, but I only check when I'm joining and unaware if I may have the game already. So much stuff out there it's very difficult to know what is what without checking... so it can be annoying. Too bad there is no features to easily monitor this at present with no add-ons at least - I don't even know if any add-on stuff has it, if it is possible to figure it out in any non-manual sort of way.

Sorry for pontificating a bit. I hope you do not mind, but I figure it's good info to be aware of! :D