Both and Google Hangouts, as well as other services like the new Chatroulette-like , seek to persuade people to put their faces on video, where computers will be able to identify them and detect their moods.

The problem is that many people (probably most people) are uncomfortable about broadcasting images of themselves in live video chats -- but they do want to interact with people online.

There are many reasons why people don't like to do video chats. They may be shy. They may want to protect their privacy. They may be afraid of being recorded doing something embarrassing.

That's why it's likely that live-capture avatars will prove very popular on future social networking sites.