The download is a couple of dozen megabytes, and it uses Google's Native Client, which provides a sandboxed environment for native code extensions. You can zoom, print, and save, and that's about it. It has the same toolbar with its limited set of features. In use, it's very similar to Chrome's built-in PDF support. Just like in Chrome OS, this support is read-only at present. Office documents open directly in the browser whether originating from links or the hard disk. With the extension installed, the desktop browser, both in OS X and Windows, acts like its Chrome OS counterpart. The Chrome Office Viewer, which requires the use of Chrome's beta or dev channels, has long been available as part of Chrome OS on Chromebooks. Google has released a beta version of an extension for its Chrome browser that lets you read Word, Excel, and PowerPoint documents directly within the browser.
