Just to clarify on that "where you at" thing....
This is not considered proper English in the U.S. (it sounds like Ebonics); it was just one of those phrases that was used on tongue-in-cheek cell phone commercials (I think it was T-Mobile, but I'm not positive).
That's the only context in which I've heard speech like "where you at," and I'm certainly not going to emulate that. I'm dumb enough as it is; I don't wish to sound ten times more stupid.
As for the perennity of text messaging, keep in mind that future technological developments will render it obsolete, probably long before it becomes significantly entrenched. The only reason it exists at all is that current cell phone systems are severely limited (especially with respect to the cell phones themselves, which provide no easy way to type text, and the messaging standards, which greatly constrain message length).
Messaging is a gold mine for telcos, though, since text costs only the tiniest fraction of what voice costs to carry, and so margins are a hundred times greater for text messaging.
Eccentric, yes, but you dumb? No. You're the brightest one here but some of the bizarre fiction you come out with...%@#!! is scary
Future technological developments won't render text messaging obsolete, except maybe if/when we never have to read. It'll evolve like other forms of communication. We still have the fax, landline phones, email and snail mail.