It was unlaunched eventually because nobody ever clicked on it. It turns out that disambiguation is a relatively rare feature for people to want when most of the query stream is navigational queries, and it's contrary to Google's goal of getting you to your answer as quick as possible (2 clicks if it were a UI feature vs. one click if the result were just in the results). AFAIK the backend is still live, but it triggers off keywords in the query rather than any UI element. If you search for [cloud weather] 100% of the results are about the meteorological phenomena, if you search for [thrush bird] 100% of the results are about the songbird, if you search for [jaguar car] 100% of the results are about the car, and if you search for [python snake] 100% of the results are about the reptile.