Google Chrome Frame brings Chrome's rendering and JavaScript engines to Internet Explorer via a browser plugin. The Google Chrome browser is based on WebKit, an open source browser engine. As Google puts it:
With Google Chrome Frame, developers can now take advantage of the latest open web technologies, even in Internet Explorer. From a faster Javascript engine, to support for current web technologies like HTML5's offline capabilities and <canvas>, to modern CSS/Layout handling, Google Chrome Frame enables these features within IE with no additional coding or testing for different browser versions.
Developing websites at present generally involves testing in standards-based browsers (such as Firefox, Opera, Safari and Chrome) which are usually consistent, and then testing in Internet Explorer. There then follows many hours of implementing fixes to work around the limitations and rendering quirks of the various versions of Internet Explorer. While the seasoned web developer can pre-empt some of these issues, there is still the occasional nasty surprise.
I don't want to get my hopes up too much, given the issues of mass adoption of such a plugin (especially in the enterprise), but this has potential to make IE compatibility issues go away. If it works, this is almost a dream come true, picking up IE by the scruff of the neck and dragging it up to the level of modern browsers.
If this approach is not directly effective, it certainly sends a much needed message to Microsoft, who have been seriously lagging in the adoption of web standards and of new, open, emerging technologies.
Google Wave currently requires the Google Chrome Frame plugin in order to work in Internet Explorer. This makes me wonder how long it may be until GMail requires it too, at least to get full functionality. Given the significance of the GMail user base, perhaps this is their route to mass adoption.