They basically have. It's called bit.ly (which is the official/default URL shortener and whose servers are housed in Twitter's data center). For all intents and purposes, Bit.ly is Twitter's own URL shortener.
But not every Twitter client and site uses Bit.ly (HootSuite uses ow.ly, for example, and Digg uses, well, digg.com). And, you know, not every short URL is made for Twitter.
(Note: this isn't supposed to be a response to the original post, which I only skimmed.)
But not every Twitter client and site uses Bit.ly (HootSuite uses ow.ly, for example, and Digg uses, well, digg.com). And, you know, not every short URL is made for Twitter.
(Note: this isn't supposed to be a response to the original post, which I only skimmed.)