But are these sites another crack in the eroding wall between public and private life? Perhaps. The better question: Do we actually care if they are? As Mr. Jones noted, Facebook’s News Feed, the feature that lets users easily track friends’ activity in one place, was somewhat controversial when it was introduced in 2006. “Obviously, now, it’s completely accepted and people who are younger, in particular, just accept it that their lives are completely open,” Mr. Jones said. (The jury is still assembling for these sites: Dscover.me has been open to everyone since November; Sitesimon and Voyurl are accepting users on a rolling basis, but will open fully in the coming months.)