I have been eyeing this crowd sourced map thing for a week or two. When I read about this headline today I learned there was a centralized app for it. I immediately downloaded it.
It's called OpenStreetMap and there are many apps for it! Organic Maps is a good one and I like it for when I go abroad and want to preload an entire country instead of downloading maps on my paltry 33 or whatever gigs of roaming allowance (that also only works in the EU - if I want to visit the US, I get to pay out the ass for 250 MB or 1 GB at a time)