Google Drive has provided a simple but powerful model for file sharing. The creator of a file can invite others to share it, as readers (read-only access), commenters (read and comment access) or editors (read, comment, and edit access). But this opens the door to all sorts of issues, like being able to make a copy of a read-only document, in which case all bets are off.
Google has taken a big step forward in access control by allowing creators to limit the sorts of things other may do with shared files. Here you see the new controls at the lower right under ‘owner settings’.
Owners can block other editors from changing access or inviting new users to access the file, and also they now can block downloading, print, and copy of the file for commenters and readers.
There is still apparently a backdoor, in that this phase of Google Drive Information Rights Management (IRM) can’t block users from taking a screenshot, or manually copying what’s in the document, as Emil Protalinski points out. The former can be controlled, but it will require a more elaborate system that can block operating system capabilities. These are the sorts of technology that extremely secure file sync-and-share solutions implement, like Intralinks and ShareFile. Google could be headed in that direction. But at the least, this is a first order degree of protection that will minimize confidential information’s mishandling.