Anything, really. For Unity, it's stuff like scripts (I.e. AI), music, textures, 3D models, complete projects, etc. The assets MA mentions, most likely are whatever is already in EU (I.e. the models, textures, sounds, and what not). Now they just hope the ICO will draw attention and get people interested in selling their assets through them, thus catering the need for their block-chain shite. In Unity, Unity takes a cut, just like the Apple Store does. What separates Apple and Unity from MA, though, is that Unity and Apple have millions of daily active users, where MA has 3 million registered accounts, with perhaps 20k monthly active (including people using multiple accounts). Unity and Apple have actual active support teams. MA has some people who copy and paste standard responses after a long period of waiting. Unity and Apple have a userbase that trusts them. MA shat on its users and partners for so long that the number of people who look favourably on them is probably at an all-time low. MA doesn't mention any of this, because it'd make anyone see that they stand absolutely nothing to gain from hosting their assets through MA's IP Exchange. What MA also overlooks is that they are counting on there being a market for monthly payable assets. Unity doesn't have that; you buy the models once, and own them. You buy a full project once, and own it. You do not constantly pay for music through Apple iTunes either. There are a few exceptions, where assets are billed on usage (I.e. an in-game shopping system, where a game developer buys that, and gets charged for every n number of transactions. Likewise, I'm sure Apple Store takes a cut for in-game transactions in games hosted through them. MA seems to think of itself as on the same level as Google, Apple, and other tech giants, but they very much are alone in that respect.