Dota 2 key Question!

nope, don't believe so.

Yes. My extra copy was from Playdota.

yeah it does i won a key from there and it came with 2 extra invites

Yes I gave Dota 2 key to my friend since I was in doubt of whether there are invites in it or not and I've no interest in the game, he claimed he received 2 invites and I asked for them, I got the 2 invites, so yeah the key DOES have 2 invites.

yes at first they gave 2 invites for 2 months but now only a game will be activated in your account. They changed this a few months ago. so you can give it to your friends without hesitation or trade.

Yes, it comes with two invites. I've got two days ago on playdota, activated and got 2 extra :)