Oo Voo will let them have a little video chat party. Unlike Tango, location settings don’t give away where you are in the world.
With this option, a friend who knows your e-mail address – presumably a friend – can find you and send you a friend request.
You could also choose “Nobody” in which case, I think someone would have to type in your Oo Voo ID directly.
Google is positioning Duo to make video chat a human experience, and from what we've seen so far they might just pull it off.
In many ways, Google already managed the "best" video chat service with Hangouts.
It gives you a reasonable idea of the connection quality, and lets you decide if you're going to answer the call quickly. You agree to accept the call and you pick up live with that person, there's no stutter to start the call or anything because it already happened when the video feed initiated a few seconds ago.
The connection is already smoothed out because of Knock Knock, and all of the settings and controls disappear so there's nothing on the screen but you and the person you're talking to.
There's obviously still plenty about Duo we don't know yet, and won't know until it is finally available later this summer.
What we've seen so far promises a lot, and it's on Google to deliver.
If Duo is able to improve on what Google already has for video chats, it's going to be a big deal.