Web of Trust.

App Store as a protocol.

Guy maintains a list of apps and either recommends to also consider others or automatically copies from these select others.

A bit like Linux distributions. Each has their own set of apps with huge overlaps but the user picks consciously a curator/distribution and adds more curators/distributions or individual apps when needed.

If we build this as a protocol, you could build tools that don't just search one person's repository of apps but all such repositories. Imagine you ask your client for "Snort" and it told you:

* 12 of your follows agree on Kieran being the maintainer of such a product addressable as Kieran.SnortSocial

* 2 of your follows list a product addressable as Eve.Snort