Even if you can search someone's gamertag, that's not what I'm refering to. In Halo 3 and Reach you could access every single map that was created by people (or game type or screenshot etc) in one place, not only in the game but also on Forgehub.com. You could look on the website and download maps from the site to your xbox. It seems like in Halo 4 you can only play on maps that you make yourself