It looks like the next battle will be for the browser of the future, allowing synchronous, presense-based interaction and security like a typical OS.  Expect to see more apps built as browser plug-ins instead of just web pages hosted on a remote server.  Google Chrome, Firefox and the new Microsoft Gazelle browsers will likely be duking it out in the not-so-distant future.

See MSFT’s research team project: [1] Gazelle browser