A animation showing edits to http://OpenStreetMap.org over the period 2007-2012.
OpenStreetMap recently had it's "State of the Map" conference (Oct. 13-14) in Portland, Oregon. This video was embedded in a great article entitled "The New Cartographers" that summarizes some of the current issues discussed at the conference as well as concerns that confont the project. The project has experienced exponential growth and is a major player in the world of online mapping (think Wikipedia for maps).
Questions to Ponder: What are some advantages (and disadvantages) to an open source mapping data set? What do you imagine is the future for the world largest open-source mapping data?