Excerpt: "Like Loopt, Google’s Latitude doesn’t (currently) keep a historic log of its users’ locations; both companies overwrite the old data each time you report a new location. We think that’s the right move privacy-wise, and hope that between Loopt and Latitude, the we-don’t-keep-historic-logs policy will become the industry standard in the friend-finding space."
They also ask: "what would Google’s legal position be when a law enforcement agency tried to make it start logging a Latitude users’ location as part of an investigation?"
I found the piece interesting.