There is a lot of value in doing things from the browser:
- You don't need to download a thing
- Theoretically, it works across operating systems
- Theoretically, it works for PCs as well as mobile handsets
- You can "widgetize" it and deploy it across multiple sites, mesh it up with other data services, etc.
There is a lot of talk these days about the real-time web: instant updates, instant notifications, instant everything. But, for some reason, this real-timeliness isn't about bi-directional video. You can do something close by streaming video in both directions, but it won't be the same.
The way I see it, the problem is that we're just now getting to the point where video telephony is suitable for use over the internet. With increasing processing power and bandwidth, but also with new innovations around video itself - for instance, the use of SVC to improve video quality.
But we're only just beginning to deal with video communications properly, and it is going to take time for the adoption and standardization to reach a stage where we can integrate it into the browser. Video telephony is barricaded with a lot of intellectual property, innovation and proprietary solutions - until all that is opened up, browsers won't be able to support it without downloading specialized plugins and extensions to handle it.
So video telephony from a browser? Not so soon.