By default, the iOS and Android interfaces aggregate at the app launcher level - you have a screen of different icons for different services, though to some extent notifications are becoming another OS-level aggregation. Anything that hasn’t been unbundled from the web is in the browser, where it is in turn aggregated by Google. Apps like WeChat and Baidu Maps move the service aggregation layer up the stack from the home screen, bundling it within a single app. Conversely Siri and Google Now (and arguably Microsoft’s Live tiles) are in different ways about moving it down the stack into an OS-level service. But the interesting thing is that changing the aggregation model also enables new types of discovery.
In the app launcher layer, any direct service discovery (as opposed to marketing, word of mouth etc) is limited to the app stores. When they launched this worked adequately, but with over 1m apps in each of the iOS and Android app stores this model is clearly now broken. Just as Yahoo’s hierarchical directory didn’t really scale after 1996 or so, so too app stores have not scaled as a discovery platform. Further, though there are lots of ways that the execution of the app stores could be improved, this still ultimately boils down to saying ‘Yahoo’s home page should be better’ back in 1996. Indeed it should have been, but the answer was still PageRank. And we have no analogue of PageRank for mobile apps."