This year is the Year of Google Documents: not only can you share your docs in the cloud but you can invite others to collaborate, that is, to edit them anywhere anytime - even simultaneously whilst you're working on the very same one!
Other must-have features include: a neat Revisions History that reveals each editor's edits in a different colour, text chat Comments in a sidebar so you can have a running commentary about content and immediate autosave (though I'm not sure if you can ever get access to previous versions...).
Of course, as your collection of docs in the cloud grows, you'll need to Organise them - this entails adding them to - you guessed it - Collections (rather than folders).
