A quick explanation of how Google Docs works:
Google Docs are for Sharing!
Google Docs = Editable + Share-able + Accessible
In other words: Every Google Doc you create you can share with other Googlers, you all can edit at the same time from any where you have access to the internet.
To try out this feature of Google Docs open this document and follow the instructions.
Google Docs includes:
Documents
Spreadsheets
Presentations
Forms
Drawings