Hi - it's actually quite different. As of now, we don't (yet) have a forward geocoding api exposed. Rather, most of the API functionality that's live is for backward geocoding. As in, with Google's Geocoder, you give a string and you get back a place. With us, you give a place (i.e. lat/lon) and you get where that place is and what's around it.

That being said, a number of people have been pinging us about getting simple geocoding functionality, so stay tuned for that as well :).