The Google Docs team shares some interesting tips in a blog post explaining the magical ways you can use the item description field in your Docs list. If you’re using the new Google Docs editor, you can type in whatever description you like to a document in the Description section found in the Docs list details pane. Most folks don’t bother with descriptors at all. But why not take advantage of the fact that the built-in search feature indexes contents of your file descriptors?
This opens up the possibility of using the description for keywords and tagging. So, if your description contains the words “Astronaut, Space” that file will show in your search results when you do a Google Docs search for “astronaut” or “space.”
You can also put in full URLs and Google Docs will turn them into clickable links. For example, you may want to attach a source Flickr link to an image in your Docs list so you could credit the source when you place the image in a document or a blog post, if necessary. Descriptions can also have basic formatting: bold (use *asterisk*), italics (use _underscores_) and strike-through (use -hyphens-).