Explanation of using a Proxy site

Hi, can someone explain what it means to use a proxy site? I see it mentioned in these forums, what is it all about? Thanks

 

You can see a (partial) list of proxy sites here: proxysites.org/
Surfers use proxy sites to hide their IP while surfing. It also allows users in certain countries to side-step government regulations, site blocks, & spying.
Proxy sites are easy to set up using free cgiproxy or phpproxy software. Money is made on them by running Adsense or other advertising banners at the top. Surfers may (actually often) surf to porn or illegal pages that are against Adsense Terms of Service to display Adsense ads on. Proxy sites try to only show Adsense on the main page and not on the proxy pages but it seems Google still does not approve. It is always dangerous to show Adsense on pages where you have no control over content. Some of the surfed-to proxied pages may already have Adsense on them and it is against the TOS to show both your Adsense and the site's Adsense on the same screen.

 

Thanks Toby, anyone else have additional info?