Google+ V/S Facebook

Google+Photos is adding facial recognition technology that will let users be tagged automatically in photos. To pre-empt privacy concerns, GooGLE (Nasdaq: GOOG) has made the feature opt-in, said Matt Steiner, engineering lead on the Google+ Photos team...
For it to work, the user must turn on the new "Find My Face" feature in the Google+ settings. Then, Google+ prompts friends and other contacts to tag the user's face whenever it appears in photos. The feature gives the user control over which tags are accepted or rejected.

Google did not respond to our request for further details.