I found this fascinating quote today:
Upon the sharing of a friend on Facebook (ahhh… the power of social recommendation…), I discovered a new service called in Flavors.me which enables anyone to build a personalized page on himself or anyone else and then link to it the main social content production factories. They currently carry 14 services including Facebook, Tumblr but also your DVD queue from Netflix, your checkins from Foursquare or the last tracks you’ve been listening on Last.fm. Once you’ve added all services, the user coming to your page can click on the services you’ve added and a window will display whatever stream of activity you’ve had on that specific service. Testing it yesterday, I mechanically added all the services I’m using including Netflix and Foursquare. Once I realized that everybody could then follow my physical traces around NY through Foursquare or all photos that I posted to Facebook (and where these only get displayed to a selected list of people), I freaked out and decided to limit that to only the safer LinkedIn and other Twitter feeds.florentpeyre.net, Social media in NY, Feb 2010
You should read the whole article.