No, it doesn't. That's not what "virtually" means. It's guaranteed, barring some unexpected advance against one of the cryptographic algorithms used. In cryptography you use words like "essentially" or "infeasible", not "completely" and "impossible," because at the end of the day you are just hiding behind hard math problems.

The whole point of OTR is that you don't have to trust the third party, and you obviously do not understand that. They are just a transport. The analogy you are making could just as well be applied to any ISP inbetween you and the person you are talking to. They are a transport. Don't trust the client? Use another. Or are you seriously suggesting writing your own? Then you're starting down a very long path: http://cm.bell-labs.com/who/ken/trust.html

You also keep comparing it to Google's "no log" feature, but they have absolutely nothing in common. The "specs are not different"; they are completely different things.

It's disappointing that you're so stubborn, arrogant, insulting to the author, and wrong at the same time. OTR is a brilliant and fascinating protocol, particularly because it gives people who communicate deniability, which PGP, for example, doesn't. Cryptocat is helping popularize it, and that's good.

This is a point which a lot of people seem to overlook. Sometimes, non-repudiation is desirable. Sometimes it is not.