So, as a rundown, this is what I heard (For those of you new to the portal franchise/never played Portal or Portal 2 before, then I hid the spoiling bits for you, although I must confess I have no idea why you would be in this thread).
Portal gloves (gloves that would make portals)
3 Portal Device.
3 Player Coop?
My theory about Portal 3 is that it, for home consoles, would be exclusively limited to the new SteamBox (PC/Mac gamers would still be able to play it), and come, game-wise, with the 3-box, which would hold 3 games: Half-Life 3, Portal 3, and either Team Fortress 3 or Left 4 Dead 3 (In regard to Half-Life 3 and Half-Life 2: Episode 3, there could be an in-game option to play Half-Life 2 Episode 3 before starting Half-Life 3. Just a thought).
Before you scoff at this, think about it from an economic standpoint. What other game, besides Half-Life 3, could shift the ENTIRE console market? What other game could shift attention away from the Xbox 360 and PS3? What other game could HOLD these people with DLC and sequels (Half-Life 4? O.o)? From my standpoint, it would be the most genius video game move ever. Portal 3 and L4D3/TF3 would be like bonuses as compared to HL3. Thoughts?
Note: at the beginning of this post I said MAY. I trust this source, but there's always the possibility.
And no, this post is not a troll. I'm not good enough of a troll to think up something like this.