You need something to stick in the users mind, a visual that they will remember. Although they can do better, at least with tent.io/tent.is you get the image of a tent in your mind which is something your subconcious can latch onto and remind you of when you are thinking about this kind of software. With Twitter in the early days the "tweet" and bird branding had a cognitive link with the product and helped keep it in your mind.

App.net is more or less an abstract title, it conjures no image in my mind, just a generic concept of software apps which has no particular generic image or symbol. So if they're going to stick with that name, they need to get some visual branding on the page to help keep user momentum. Because at the moment, press momentum is dying and they'll quickly become yesterdays news as people forget them.

I don't know if it is a priority, but the name is horrible. And alpha.app.net?? Not pretty.