The greek FAQ isn't crystal clear when translated, and "seekers" is only making me think of quiddich, but definitely seems like a way to turn finding a parking space in a busy/heavily populated dense city into a game, not sure it would work anywhere else though!
They just launched in Athens for beta testing purposes but they are working on bringing in in some selected urban areas. It needs a good community and that's something hard to build.
Also if you download the application, there is a demo mode inside and you can see the real application functionality with test data.
If you own a car, you'll definitely find it useful. Really well designed and great execution. As every crowd sourced app, needs support from the community, so it takes time to build. It will get there.