Jonathan Bray - I can see video replacing SMS supremacy as ease of use increases. It wouldn't surprise me if we get video avatars to deal with the whole "messy hair and pajamas issue". When you can map a video avatar of your "Best Face" (or random character) that actually responds to your minor facial movements we'll be there. Not only that but short burst facial responses would grant so much interpersonal contact that it will replace texting lol, WTF?, and the likes.
Video communications will become the standard for businesses offering premium customer service, and savvy businesses that want to increase interpersonal engagement.
Tech issues like multitasking and bandwidth will be worked out over time, and are not insurmountable enough to prevent mass adoption.