[bityard]

I remember this as well and thought it was a neat service. One that I would have liked to emulate using my own proxy in order to save bandwidth on my mobile data but never got around to actually doing.

These days with widespread HTTPS, the only way to do this is to bake it into the browser itself.

And of course, this was back when you could trust Opera to do what they said they were (or weren't) doing.