There are services you can pay for such that you can route internet traffic thru a specific IP in a specific part of the world. People (usually unwillingly and unknowingly) run software that effectively makes them part of a giant botnet. A computer running in Romania might have some kind of weather application or gambling/casino app that I could use to make an HTTP request as if I were on their network. So if you need access to 1,000 or 10,000 IP's to circumvent rate limits or perform crawling tasks, this is how you could do it.