[noxToken]

I think Reddit is not quite analogous to the other sites listed. Excepts for posts being deleted or stickied, all content is sorted democratically on a timer. You have the option (by default) to additionally sort by newest or newest post that are also popular with users. I'm sure other Reddit mobile clients have this functionality as well.

[jsprogrammer]

As far as I can tell, the other sites listed implement only a subset of reddit's functionality.