Google will probably integrate it with Gmail, which is already a huge communication hub for so many people.
But the fact that Google is using open-source software suggests that the company wants third-party developers to build WebRTC into Web applications.
In a blog post, Google wrote that it wants "to implement this technology for use by the broader web community," and that they've "engaged with the standards communities such as IETF and W3C working groups to define and implement a set of standards for real time communications."
Microsoft/Skype should be shaking in its boots.