For Google Glass critics concerned about privacy, there's a new factor to consider: live broadcast.

On Tuesday, Google Inc. officially began offering the Livestream video-sharing app in its MyGlass store. The software lets Glass wearers share what they are seeing and hearing with other Livestream account holders free of charge by using the command, "OK Glass, start broadcasting."

Users who want to broadcast to non-registered Livestream viewers can pay up to $399 a month to stream their video to the Web.

The app, available in beta version since the spring, was one of roughly a dozen, including music-recognition service Shazam and a star chart, that Google unveiled as it gets ready to kick off its annual developers conference and rolls out Glass to the public.

Livestream LLC, the namesake software's Brooklyn, N.Y., creator, figures doctors could use the app as a teaching tool during surgery, or that spectators could share their experiences at concerts or at the ballpark.