If you've used Ubuntu for some time already, you'll know that proprietary drivers get installed by this little app called Jockey. It's best known for helping in installing proprietary nVidia/Radeon GPU drivers but it's not limited to just those two.
Wifi cards, modems, etc,. all get their drivers through Jockey if there's no open source driver available. Same goes for when the proprietary driver enables features not available through open drivers.
This wonderful tool looks like it's getting some attention other than adding more drivers to it. Check out the blueprint for more info.
Check out the draft design to get an idea where the developers are heading with Jockey's redesign. It looks like Software Sources will get collapsed together creating a new tool.