Google is launching an online spreadsheet that will let you load Excel files and share documents online. Up to 10 people can work on the spreadsheet at the same time - the names of people editing and reading it will appear in a chat window. Users can save the documents to their Google account or export them as .csv, .xls or html files. Like the launch of Gmail, Google is limiting the number of new users for software - still in beta - to avoid overloading its systems.