When FB was rolling out ipv6 in 2012, well meaning engineers proposed releasing a v6 only GeoIP db (at the time, the public dbs were shit). Not surprisingly, it was shot down.
They recently added GeoIP to their data and in the bit of testing I was able to do before I left it was scary good. I also had an amusing chat with one of their engineers at a conference about how you can spoof IPInfo's location probes...
Interesting. I would love to know how this is possible. Like with Geofeed or something else?