Siri
A company spun out of SRI released an application that understood a spoken request and carried out the action itself, booking a table or calling a taxi.
Why it matters
Voice became a command to a system that acts for the user, rather than a query to a search engine.
The project grew out of DARPA's CALO programme, the largest personal-assistant effort of its time. The application spent two weeks in the store before Steve Jobs took an interest; Apple bought the company in April 2010 for around two hundred million dollars. Siri shipped as part of the iPhone in October 2011. Forty years separate this from Shakey, built at the same laboratory.