Most people, SEOs especially will have heard of and understand what proxies are. For those of you who don’t know, proxies allow you to “tunnel” your browser’s traffic through another computer, making it seem like you are surfing the web from that location. There are specific services out there that make your traffic more anonymous by doing other things like blocking cookies, or even certain sites. Those web filters that keep our kids “safe” are a type of proxy (although most are easily bypassed.) Most proxies are owned by companies to which you pay a fee for their use, or you can search for “open proxy list” to find some. The downside to using these is mainly lack of control – you have no control over if the proxy is forwarding HTTP headers (making it known that you’re using a proxy), no control over DNS or who else is using the proxy. I’ll explain why these are important shortly.
If you’re optimizing for US-based or UK-based traffic it doesn’t make sense to check your SERP ranking from Canada. What if your site is in a foreign language such as Italian? It makes more sense to search from an IP that is geographically located in the area you’re trying to analyze. That’s where proxies come in. You simply have a web proxy set up in a data centre in the right country and you’ll instantly have a more accurate picture of where you rank in the SERPs. We can set proxies up in a variety of locations such as Canada, US, UK, or other European countries such as France and Germany.. These are dedicated servers with dedicated IP addresses, configured to not add HTTP headers that tell others you’re proxying. These servers are dedicated to you, and cannot be used by anyone else. There are lots of dedicated proxy service online.I recommend you find those service on http://privateproxyreviews.com.
If you run any kind of SEO tool, you’ll know proxies are a must. Those of us without Google API keys must rely on “scraper” type tools that do repeated searches. These tools are not scalable from one IP, meaning you hit a threshold and your tool stops working (I hate it when that happens.) If you proxy your requests through several different dedicated proxies, you can avoid this. And for those of you who use open proxy lists – they are unreliable, slow, insecure and remember that you have the list as well as thousands of others, including the search engine companies. Dedicated proxies are reliable, fast and they belong to you. You control who has access from where.
Developers can use dedicated proxies to test applications quite easily. This is especially important if your software does anything with IP geolocation data, such as taking users from the UK to a different domain. The only surefire way to test this is from a UK-based IP. Perhaps you’re in the process of upgrading your site and want to test it one the “live” domain name before making the DNS switch. You control the DNS resolution on your proxy, so you can make your site resolve to a different IP through the proxy. This allows you to flip back and forth between the old and new sites.
From:http://coastalweb.ca/system-administration/dedicated-proxies-for-seo-and-developers.html