I believe the answer is: nowhere.

Everyone is trying to use less useful things like twitter and facebook and G+ and perhaps tumblr and such. But my impression is that it really just means people - myself included - just aren't posting the kinds of things they used to.

And being out of the habit means that other things took their place (or didn't). I don't post much anymore because I'm out of the habit, and because I'm in grad school, and and and.