Eventually, as the technology progresses, Twitter will outlive its usefulness. As much as people enjoy yelling out into the void and seeing what other people yell back, Twitter will only last so long. Like AOL, MySpace, and others before it, it will die a slow death as newer, fancier ideas supplant it. This may happen in two years or in twenty, but when it succumbs we won't mourn it for long. We'll adapt and keep on going, because no matter how the media evolves, we'll always have something to say. At least, I know I will.
My whale is too big to fail.
(Okay, so I really just wanted to mess with Twitter's imagery. Not that it makes anything I've said any less true...)