What it says on the tin, really. I think this is going to be an issue when they get around to the smaller communities... It's going to suck majorly, as most people's default will remain with reddit for community discussion like this...
Honestly, for me it's not so much what they did, but rather how they went about it. To clarify, them wanting people to use the official app is fair enough, but instead of market economy, i.e. providing the superior product, they went gilded age capitalism and try to hulk smash the competition, and that's just not on for me.