This question is just coming out of curiosity ...
I am behind a proxy server and am using some anonymous online proxy from behind it. Can my internal proxy server see what requests i am sending and receiving from the anonymous proxy ? I know that the outside world sees that as if the anonymous proxy is requesting something .. but is it possible that my internal proxy server knows the same requests ?
If the connection between your local machine and the outside proxy is not encrypted, then it is possible that your inside proxy can see the requests that you are making.
TOR (https://www.torproject.org/) solves this problem, by relaying your requests through multiple proxies, using an onion-like encryption scheme where each proxy 'peels off' a layer of encryption one-by-one. This way, only the last proxy can actually see your request, but this proxy has no way of knowing where this request originated from.