Collaborative writing with Google docs

In my last post, I discussed the benefits of doing collaborative research in grad school. With the brilliance that is Google docs, team writing is a smoother process than ever. I know that some have been using Google docs for years, for both collaborative writing and their own personal work, whereas there are many who have yet to try out the feature. (If you fit in the former category, some of what I'll review here is pretty basic, but I encourage you to read through and comment to add any functions or perks that I've missed here.)

How I use Google docs & my favorite features:

1. Writing text: Obviously, a main function of Google docs is that you can write within a window just the same way you could within a word processor. You can change the text style, size, color, and more similarly to a word processor. It has less features - fewer font options and no text boxes, for example - but offers many of the basic functions you need. I use the word count tool a lot! 
2. Exporting: When you need to finish something off in Word (or put it in a .doc format to send off somewhere) you can easily export the document as a Word file, or even a PDF or RTF file. 
3. Collaborative writing: The main advantage Google docs has over a word processor is the facilitation of collaborative writing. As you type, others who are viewing the document (or "in the document) can see what you are writing in real time, and vice versa. I can immediately edit a word someone else has written, we can cut and paste each other's writing - it's all real time. Which is connected to the awesome feature for group projects of - 
4. Everyone is immediately updated: When you open the document, everyone who has permissions to it all have the same, most up-to-date version. No more sending around docs and keeping track by having "GrantAppVersion02Edit34." Work on it in Google docs until everyone is done and then download it in whichever file format you need. 
5. Chat function: Within the document, if another writer is also viewing at the same time, you can chat with your collaborator about the project (or anything else, for that matter). It's helpful for discussing the plan of attack, setting a schedule, etc. all while you are working on it. It also helps save valuable in-person meeting time. (Edited to add this item post-publication - I forgot in my haste to get this posted!)
6. Flexibility: With a word processor, spreadsheet, and presentations, you can create a doc for pretty much anything you need. I've got docs for essays, group projects, as well as lecture notes, reading exam lists, and Christmas present budget for last year. 

Clearly, I'm enamored by Google docs, but I don't think it's perfect. I find the "filing" system a bit clunky - like Gmail, you can tag things, but creation and maintenance of the folders is not so easy. The apps for your smart phone aren't perfect and make it difficult to edit a doc on the go (if you think that's what you will mainly use it for. That's not a primary need of mine, so this isn't a big problem for me, but others tend to prefer something like the Evernote app over the Google doc app). Finally, when you download a doc as a Word file, the formatting does not export as cleanly as I'd like - I tend to spend 15 minutes tidying up the spacing, adjusting the rules, and formatting the font to make it the professional document I need it to be.

Regardless, Google docs is still a great new(ish) tool for PhD students. How do you use Google docs? Any cool ways to use them that I haven't mentioned, or additional concerns I haven't thought of?