jshackles
Gentlemen, we can rebuild it. We have the capability to make the world's first enhanced store. Steam will be that store. Better than it was before.
EGG incoming
In all seriousness, I'm extremely interested in how GOG Galaxy is going to tackle playtime tracking and whether or not they decide to integrate it with their social system or not. On one hand Steam does really well for this, but doesn't track game time for non-Steam games. On the other extreme opposite, sites like Raptr track absolutely everything but lack any sort of understandable cohesion when it comes to unifying that data in a meaningful way.
Just spitballing stuff here, but using GOG's infrastructure it may be possible to make a hybrid GOG / Steam client (you'd still need the actual Steam client, sadly) but it could unify all of your GOG and Steam games into a single place. GOG would still track your game time (presumably, depending on how it's set up) regardless of where the game is launching from.