Today Google opened up their Map Maker service to the US. This tool allows users to make changes and additions to Google's already incredible map database, and these edits will be made available through both the Google Maps and Google Earth interfaces after they've been vetted.
I'm currently in the process of adding my project's lease roads to the system. Once they've been approved, a map of our field (currently a mess of unlabeled roads) will actually be navigable with a simple printout: a fantastic improvement for new employees, visitors and contractors.
A small section of the project I work at:
View Larger Map
One part of this new tool I particularly like is being able to see edits made in real time, all over the world.
The only drawback I can see is that all information uploaded to Map Maker becomes proprietary Google information, not open sourced. But hey, I've been using the free maps for years now, so if I can contribute back a little bit and improve my personal experience at the same time, I'm all for it.