Do you remember the first social networking site that got popular? At least in this part of the world I feel it was orkut. There are other sites more advanced and user friendly than orkut, yet orkut remains to be a classic example of a social networking site. I still love the idea behind leaving a scrap. So simple. Less noisy. Beatific. But orkut has been privy to many cultural & privacy problems. It was blocked in Iran because the Islamic community there had strong views about dating, etc. After the Iranian government blocked the site, there have been a lot of proxy sites which allowed you to access orkut. Proxy sites allowed for anonymous browsing of orkut pages. During those times orkut pages were fairly simple I guess. Later google disallowed anonymous browsing over its secured http page. Actually google did a lot of things. The most prominent thing you might always miss is the Loading... part.
This is what google did to render proxy browsing useless. So here is a little about how orkut page gets loaded. After you provide your username and password to log-in to the site, you are taken to the main page (Home.aspx#Main). From a web designers perspective this is nothing but an empty page with place holders (like your friend list, upcoming birthdays, friend updates, etc) where data & images are supposed to sit. These place holders are not marked to be visible to the user. Hence the net effect is a nearly blank page except for the background color and all. (You are welcome the view page source of the orkut main page to testify this fact).
So you might be wondering how does ajax figure in all of this? Ajax is the technology via which the orkut main page makes simultaneous calls to the orkut apis to fetch social data.
So how does security actually figure in this? How does it incapacitate proxy/anonymous browsing? This is where you need to understand how proxy browsing works and how a normal browser works. And brace yourselves, this might sound too technical.
I won't say proxy browsing can be obviated completely. It is still very possible. But its a hell lotta work. Sometimes it better people simply enjoy the site rather than hacking it.