Google is in the process of increasing the collaborative possibilities of Google Docs to compete in a cloud based, social web world.
Some of the new spread sheet features include: margin ruler, better numbering and bullets, and more flexible image placement, formula editing bar, cell auto-complete, and drag-and-drop columns. Also, since they upgraded the infrastructure supporting Google Docs, large spread sheet will be easier to manage.
The new collaboration features will work very similar to Google Wave--Google's online social collaboration tool. This will allow up to 50 editors to be able to work on the same document simultaneously.