If you are looking for better visibility into how your Google Docs are shared across and outside your enterprise, it might be worth your time to examine CloudLock. While the service has been out for more than a year, it has recently gotten some new features that make it more compelling.
Other actions that can be done include the ability to quickly transfer ownership of a particular user's documents to someone else. This would be useful when an employee is about to leave the company, or if you need to clone their workspace. The system can operate either just for the Google Docs admin, or can be enabled for particular end users to see what is going on with their own documents. You can select multiple documents to change with a single operation, such as terminating access for all private Gmail accounts for all documents. And individual users can quickly search across the domain for particular keywords or other document properties that are shared with outsiders, which is great for eDiscovery purposes.
There are several useful reports that can be run, including a change report that shows you what has changed over a particular date range with your documents, a historical summary of which documents are classified by the system (externally owned or exposed to the outside), and an audit log that shows you what adjustments to document permissions were done by the system. Reports can be scheduled to run on a regular basis, such as every Monday and Thursday.
The service is available for a week free trial and is free for domains for less than 10 users. Otherwise, it is $8-$19 per user per year. You can activate the service from Google's App Marketplace here. There were other Google VMworld-related announcements this week, including our story today on App Engine pricing changes.