I was reading that a large porn website was banning access from North Carolina to protest their new LGBT law. This made me wonder: how do you identify a user/group of users from a particular geographic area? Is it something to do with IP addresses? Are the IP addresses in a given geographic area similar, such as having the same number codes in the address?
There are large databases that have rough geographic information for various ISP routers and even countless home and small business WiFi SSID's that were geo-located by people's smartphones to aid in improving GPS data when the satellite signals are blocked or not reliable. Many routers have an option where you can actually input their latitude and longitude voluntarily in them as well, which is used for the various fancy maps of a country or the world showing airline route-like lines going around from city to city. YouTube, Netflix, and other services use data like this to block or show movies/videos that may be copyright restricted in certain countries for instance.
(The wide array of Hitler "Downfall" parodies with alternate subtitles for instance are all blocked in Germany by YouTube, but can be viewed in America where they come under "fair use" stipulations of Copyright for "parody" etc.)
However, there's problems with this, the databases are constantly changing etc. and there's inaccuracies, and some randomly chosen "dumping grounds" for IP's that don't have reliable geographic data in them. Like these poor people:
http://fusion.net/story/287592/internet-mapping-glitch-kansas-farm/And the geo-location, depending on the way IP info is reported by the ISP can show you in a completely different state at times. For instance, Facebook records my home access through AT&T U-Verse as being in Michigan at times rather than Wisconsin. And my smartphone with Verizon often shows up as Texas...
Someone using this data could certainly inconvenience a large portion, say 80-90% of a state's users accessing your site this way if they wanted to. And a savvy user could easily get around it too.