Their analytics is clearly their core. Twitter may have a giant Network, but they need to make more connections out of that Network to truly add value. Bit.ly is an example of a service that puts connections together and creates value. But they’ll have to think of something beyond just a Digg clone.
But bit.ly is dependent upon the Twitter service. As Twitter goes, so goes bit.ly. Not the best position to be in, until the service truly gains mass appeal (Google). Services like SEO, SEM, and a whole lot of other products are built on the Google platform. Twitter’s not there yet, and it’s early in the Real-Time search/data game.
It’s all about the Network.