Google Docs has a feature called Collection which would help users to organize their files. Selecting a specific file in the Document list would be difficult when you have large number of files and Collection could come handy in these scenarios. For example if you want to separate your work files and personal files then you can create Collection for each category and group the files accordingly.
You can create a new Collection by clicking the Create new down arrow and selecting Collection from the menu list.
Enter the name of your Collection and click Ok button (Not sure why this window name is Rename?).
The new Collection will be listed under My Collections
Now navigate to Document List then drag and drop the work related files under this Collection. Files under any collection would be highlighted in the Document list as shown below.
Thus Google Docs users can group the files under Collection and Organize their files.