CNET reports that Twitter has admitted to saving more than your tweets when you use their app on your smartphone. Twitter is uploading your contact data and browser history and saving it on their servers for 18 months. For what reason???
A spokesperson for Twitter says that in the next release(s) of the phone app(s), they will be more explicit about what Twitter does and does not do.
Learn more from the CNET video (1:30): Twitter wants your contacts, smartphone data