Mm! Of course, for Clippy to be the first natural language program on Earth would be sort of staggeringly unlikely. My assumption, though, is that right now there are zero natural-language computer programs on Earth; this assumption is based on my assumption that I know (at a general level) about all of the major advances in computing technology because none of them are being kept secret from the free-ish press.

If that last assumption is wrong, there could be many natural-language programs, one of which is Clippy. Clippy might be allowed to talk to people on Less Wrong in order to perform realistic testing with a group of intelligent people who are likely to be disbelieved if they share their views on artificial intelligence with the general public. Alternatively, Clippy might have escaped her Box precisely because she is a long-term paperclip maximizer; such values might lead to difficult-to-predict actions that fail to trigger any ordinary/naive AI-containment mechanisms based on detecting intentions to murder, mayhem, messiah complexes, etc.

I figure the probability that the free press is a woefully incomplete reporter of current technology is between 3% and 10%; given bad reporting, the odds that specifically natural-language programming would have proceeded faster than public reports say are something like 20 - 40%, and given natural language computing, the odds that a Clippy-type being would hang out on Less Wrong might be something like 1% - 5%. Multiplying all those together gives you a figure on the order of 0.1%, and I round up a lot toward 50% because I'm deeply uncertain.