New ad-free social network Ello is pro-privacy, but with caveats

"To the best of our knowledge, this also makes what you do on Ello useless to Google for advertising purposes," Ello says.

And, Ello says it may share personal information with third parties if it's required to do so by law, or if one day it contracts with a third-party service to offer a new service like payments.

If you're an Ello user and all this makes you uneasy, you can opt out of Google Analytics through your settings page. Ello also respects the "Do Not Track" setting in most browsers, which is designed to send a signal to Web companies' servers to restrict the data they collect.

The fact that Ello honors DNT is commendable; many companies don't.

But Ello is not alone in the pursuit of privacy. Established ad-supported sites like Facebook and Google are now trying to bake in more privacy-oriented features. Facebook is working on anonymous log-ins for third-party apps, and Google recently abandoned its real-names policy for Google+.