Arguably more an expansion of the original idea than a pivot, but Twitch used to be justin.tv which was just a single 24-hour livestream of Justin Kan, they later expanded it to allow other people to broadcast as well and then noticed their gaming channels was doing really well and rebranded as Twitch to solely focus on gaming.
From Justin.tv (the streaming service) to Twitch (the gaming-focused streaming service) was definitely more change in strategy (focusing on what was organically working best), but the original change really was a pivot from content creation (which happened to need the ability to stream) to providing others with that ability to stream as a service.
