Comment It's not a game changer (Score 2, Informative) 109
If you're a nosy marketer, it gets worse. We're moving from a browser-centric to an app-centric world. Every time you access the Internet through a particular app -- Facebook, Gowalla, Yelp, Foursquare, and so on -- you're surfing from within a walled garden. If you click on a link, all the marketer sees is a new visit. The referring URL is lost, and with it, the context of your visit.
This isn't true. All these sites do a 301 redirect (well bit.ly certainly does) so you won't lose the referrer or the context. Really this doesn't do a lot for the analytics of a site, apart from it is going to help Twitter work out how many people have clicked on which type of link (and if you're logged, who you are). It's giving them some more ammunition for contextual advertising.