Remember MySpace and Bebo? Most western people moved to Facebook, and there’s no reason why we might move again in the future. Yes, it seems unlikely, but that doesn’t mean it is forbidden.
The Unfortunate Tale Of Two Twitters sums up how a single internet company should not expect to own its users and win.
To say, as Twitter appears to have, “only Twitter should be building Twitter clients” is just ridiculous. Few of the people I follow use Twitter’s own clients to access and contribute (neither do I). They are going to love having their preferred method killed (not).
As Dave Winer says: Twitter has now become something to route around. And that means it is dead to some extent.
Those companies that allow reasonable freedom to build products and services around their infrastructure should have greater longevity. (Think Google and email: I can pay for their service, but use, e.g., Thunderbird to access it without ever seeing Google branding or ads.) Finally, building on web standards means you don’t have a platform or a vendor: that’s properly powerful.