The marketing of apps has switched from "we're making old styles of connecting easier" (i.e. Facebook being a re-hash of existing college facebooks) to "you would never have really wanted to do this in the first place, but now it's easy so you will."

Word of mouth is STILL the best way to spread ideas, which is why platforms such as Twitter and Facebook remain viable. They're capable of being used in all sorts of ways, but their core strength is that they're simply about connecting people and then letting people decide how they want to share information. The more app developers attempt to structure what information people are sharing, the less useful the tool becomes - especially when it's information that was never really shared in the pre-social web age.