When I use google for geocoding most the addresses still seem to be returned as 'RANGE_INTERPOLATED' so it doesn't look like that part has advanced much.
Well, sure. That's how addresses work in the US. It used to be that geocoding essentially only worked for US-style addressing systems.
I think Google has gotten a bit more advanced by basically doing OCR from street view to make a non-linear relationship along roads. The US address system is still fundamentally a linear referencing system, though. Interpolating between endpoints is how it works.
There's still plenty of incorrect information out there in databases, though.
For example, all the addresses on the street I grew up on are on the opposite end of the road due to the record in the BTS shapefile I mentioned having the start and end addresses reversed. That error has propagated through Google, Bing, and everything else I've seen.
