YouTube created the world’s largest online video-sharing platform before Google acquired it in 2006.
YouTube was founded in 2005 by Steve Chen, Chad Hurley, and Jawed Karim. The service made it easy for ordinary users to upload, watch, and share videos through a web browser. Google announced its acquisition of YouTube in October 2006 for $1.65 billion in Google stock.
The acquisition helped Google expand beyond web search and advertising into online video. YouTube later became one of the internet’s most influential platforms, supporting creator channels, advertising, live streams, music, and educational content.
This question concerns the acquired company itself, not Google, which became one of the world’s largest companies by market capitalization. Vimeo, Dailymotion, and Twitch are also video platforms, but none is the company Google bought in 2006.