Google Docs & Spreadsheets is a convenient Internet service for writing and saving documents independent of the computer you use to connect to the Internet. Documents that are stored in this way won't be lost, for example, if your hard disk crashes, and it has the additional advantage that you can easily share documents with friends or colleagues.
If you do most of your work on the Internet, it is also easier to switch to a new computer and to a different operating system, since all you need to get up and running is a browser and Internet connection.
There is no limit specified for the total amount of disk space you can use in your Google Docs & Spreadsheets account, but the limit for each document is 500KB plus 2MB per embedded image. Spreadsheets are limited to 10,000 rows. These generous allotments are made possible is large part by Google's extensive use of Linux servers and Open Source software.
You can download your documents to your local computer in various formats, including OpenOffice, HTML, RTF, Word, PDF, and plain text, and you can upload OpenOffice, HTML, Word, PDF and text documents.
Google asserts that all your documents are private and only readable and accessible by you, unless you make them public or share them with others. For more information on setting up your own Google Docs & Spreadsheets account, go here.