This is a good think piece by Benedict Evans from Andreessen Horowitz:
Today, app stores look a lot like the Yahoo of 20 years ago, and they don’t work for the same reasons – you can browse 20,000 apps but not a million. Hierarchical directories don’t scale. And so while it’s easy to make a list of things that Apple and Google should fix on their app stores, that misses the point – it’s like making a list of ways that the Yahoo home page should have been better. You might have been right but the answer was still Google. (I suspect that the same applies, just a little, to the current moves towards app search and deep linking, incidentally. PageRank uses the signal of links between pages – the ability to link of itself is only half the picture.) This is one reason mobile messaging apps are so hot – because they might become acquisition and discovery channels.
However, I think our preoccupation with the problems of apps and app stores and with the ways that they broke Google masks a deeper issue – that Google didn’t really solve the problem either. Or rather, it moved the problem. Google is very good at giving you what you’re looking for, but no good at all at telling you what you want to find, let alone things you didn’t know you wanted. Like Amazon, it’s essentially a passive product (which is why Now is so interesting). It relies on waiting for you to find out what you want somewhere else, in some other way, and then it gives it to you. No-one complains that ‘I put my book on Amazon and no-one can discover it there’, but that’s really no different to saying ‘I put my app in the app store and no-one can discover it there’, or indeed ‘I made a web page and no-one came’.