tedster - 5:23 pm on Sep 28, 2010 (gmt 0)
That kind of data is where the really big bucks are, and Twitter is just a beginner in the race. It's why we've seen Facebook being so casual with privacy.
If any company doesn't explicitly guarantee you a certain kind of data privacy, then they can and often will monetize the rest of the data that you expose to them. Many ISPs sell clickstream data to many takers.
The practice not even close to new. Offline it's been going on for decades with catalogs and other kinds of direct marketing.