https://www.gamespot.com/articles/valve-accidentally-launched-its-twitch-competitor-/1100-6461242/

[Update] Steam.tv has been taken offline and, in a statement to CNET, a Valve representative said it was meant to be an internal test and was made publicly accessible by accident. "We are working on updating Steam Broadcasting for the Main Event of The International, Dota 2's annual tournament," the company explained. "What people saw was a test feed that was inadvertently made public," said the company."

[Original story] Valve, which runs digital game distribution platform Steam, has launched Steam.tv, a video streaming portal that could be direct competition to Twitch and YouTube. Steam.tv is currently showing Dota 2's The International, with no option to watch any other games or stream to the service yet. However, it's likely that both of these features will be introduced in the near future.