Opera Mini does still "turbo-proxying" i.e. tunnels all HTTP requests through a proxy server over on TCP/IP socket. This seriously improves loading performance.

Normally each HTTP request opens its own TCP/IP socket, each socket needs handshaking and there is serious latency issue with radio networks, pages load slow over 3G.

To have a special proxy server needs infrastructure, though. Opera is willing to invest, but I am not sure whether there exists any hackish solutions for open source community.