While a portion of many terrestrial broadcasts have made it into space unintentionally as a side effect of the broadcasting process, it wasn't until a promotional stunt by Frito-Lay that humanity sent an intentional advertisement into space.
In 2008, as a quirky promotion for their popular Doritos chips, Frito-Lay sponsored a fan-created advertisement contest. Matt Bowron and John Addis from Highbury, London were not the winning commercial shown here on Earth, but it was also broadcast into deep space.
On June 12, 2008, the winning was beamed, using the powerful radar array at the EISCAT Space Center in Svalbard, Norway, at a solar system in the Ursa Major constellation, 42 light years away from Earth. In 2050, any inhabitants of the distant solar system properly equipped to look for signals from alien worlds will be in for a treat.