Lawsuit protection and the pairing of tweet data with internal demographics data? There’s no telling what Twitter knows about its users from being installed on their phones(geocoding, network analyzation, etc.) to analyzing their advertisement engagement to sentiment analysis of word choice and it goes on and on.
As stupid simple as the tweeting/re-tweeting mechanisms are, that doesn’t mean they don’t have serious targeted marketing algorithms and other high end data analysis tools behind the scenes. It would be silly if they didn’t.