Google Docs & Spreadsheets

Simplemente, genial; Google Docs & Spreadsheets:

We took Writely, the Web word processor, and integrated it with Google Spreadsheets. The result is Google Docs & Spreadsheets -- one place where you can create, store, share and publish your documents and spreadsheets online. (Bookmark this: docs.google.com.) Keeping your documents and spreadsheets online is a treat because you can access them from anywhere via a Web browser. You can also get feedback and contributions from others you invite without having to email around copies of files, because the current version is always online.

(Vía Official Google Blog)