I know for Networking They used ULink. I was talking about the Streaming aspects. ULink sucks, but the issue is alot of people have very few choices for MMORPG's ... Unless they make there own custom solution..... I won't make large games like MMO's in Unity personally. Anything with alot of people I would rather use Unreal or an in house engine . Every Unity game that I have seen that has alot of people in the same location , suffers badly. Unity needs to make games like MMO's better.. Which I know they planned to fix some of the many issues related to large MMORPG's Its too painful of development making those type of games in Unity , from what I have seen and played. and experienced myself.