Google Docs is adding a key feature that makes it a true competitor to Microsoft Office: offline access. It's promising, but the early beta I tested had limitations.
The offline version relies on Google Gears, an offline syncing technology; once Gears is installed, Docs syncs your documents between its servers and your browser. You can then access docs.google.com offline, and all changes you make to documents are saved when you reconnect.
That's the theory, at least. Gears installed fine on Internet Explorer (though it didn't work for me on Firefox 3), and when I reconnected after making changes offline, it seemed to sync up. But the changes never made it to Google's servers; I could see edits when I viewed the document in IE on my own PC, but on other browsers and other PCs, the changes vanished.
I tried again on a second PC, and everything worked fine. I could edit offline, synchronize, and see my changes in other browsers and on other PCs.
The offline tools are limited. You can't create a new document, look at a document's revision history, change the document style, insert photographs, or check your spelling.
I can work around most of what's missing in the offline version (but if you can't spell, you may feel differently!). Google needs to do some further polishing to make Docs work seamlessly with Gears, but once it does, this could be a great tool.