Proxies make it possible to get to sites that are blocked by firewalls or content filters, typically at computers at work, school, or the library. The problem with proxies is that they have a limited lifetime. As filters become aware of them, the proxies get added to the list of banned sites too.

PrimeProxies is not a proxy site. It's a site that lists proxy sites. It keeps up to date on new proxy sites and it takes sites off its list as they become blocked by filters or if they go under for other reasons. Of course, it's only a matter of time before PrimeProxies itself is blocked. That's why they have an email option. It allows you to get emails (at a frequency of your choosing) with the latest proxy locations. As long as you can get to their site once to sign up for the email you'll have a steady supply of proxy sites available to you.