What is Anonymous Proxy Servers?
In an enterprise that uses the Internet, a proxy server is a server that acts as an intermediary between a workstation user and the Internet so that the enterprise can ensure security, administrative control, and caching service. A proxy server is associated with or part of a gateway server that separates the enterprise network from the outside network and a firewall server that protects the enterprise network from outside intrusion.
A proxy server receives a request for an Internet service (such as a Web page request) from a user. If it passes filtering requirements, the proxy server, assuming it is also a cache server, looks in its local cache of previously downloaded Web pages. If it finds the page, it returns it to the user without needing to forward the request to the Internet. If the page is not in the cache, the proxy server, acting as a client on behalf of the user, uses one of its own IP addresses to request the page from the server out on the Internet. When the page is returned, the proxy server relates it to the original request and forwards it on to the user.

What is Anonymous Proxy Servers?
Anonymous proxy servers hide your IP address and thereby prevent unauthorized access to your computer through the Internet. They do not provide anyone with your IP address and effectively hide any information about you and your reading interests. Besides that, they don't even let anyone know that you are surfing through a proxy server. Anonymous proxy servers can be used for all kinds of Web-services, such as Web-Mail (MSN Hot Mail, Yahoo mail), web-chat rooms, FTP archives, etc. ProxySite.com - a place where the huge list of public proxies is compiled. In a database you always can find the most modern lists, the Proxy are checked every minute, and the list is updated daily from various sources. The system uses the latest algorithm for set and sortings of servers by proxy, servers for anonymous access are checked. Results of Search always can be kept in file Excel.

Why Should You Use Anonymous Proxy Servers?
Any web resource you access can gather personal information about you through your unique IP address ?your ID in the Internet. They can monitor your reading interests, spy upon you and, according to some policies of the Internet resources, deny accessing any information you might need. You might become a target for many marketers and advertising agencies who, having information about your interests and knowing your IP address as well as your e-mail, will be able to send you regularly their spam and junk e-mails.
A web site can automatically exploit security holes in your system using not-very-complex, ready-made, free hacking programs. Some of such programs may just hang your machine, making you reboot it, but other, more powerful ones, can get access to the content of your hard drive or RAM. Everything a web site may need for that is only your IP address and some information about your operating system.

The Solution:
Using an anonymous proxy server you don't give anybody chance to find out your IP address to use it in their own interests.
Some websites publish some anonymous proxy lists.Because free proxy server offline very fast.So the free proxy lists must be freshed frequently.