5 Rebecca Black
On February 10, 2011, unknown singer Rebecca Black uploaded a low-budget video of her song "Friday" to YouTube. The song went viral, inspiring countless parodies and receiving millions of views within a few weeks. Subsequently, Black earned an appearance on "The Tonight Show" with Jay Leno, and her song was noted by pop celebrities like the Jonas Brothers and Bieber.
4 Soulja Boy
Rap music singer and producer Soulja Boy is well established as one of his genre's top entertainers. This wasn't the case when he created his YouTube web page in 2004 to showcase his music to the world. He was soon discovered by Atlanta producer Mr. Collipark, and the pair worked together to produce the 2007 Grammy-nominated song "Crank That."
3 Sophia Grace and Rosie
When the parents of these two childhood friends in Britain uploaded their cover of Nicki Minaj's "Super Bass," they likely had no idea what would follow. The video went viral and led to several appearances on "The Ellen DeGeneres Show." The girls sang songs, met their favorite celebs and even represented Ellen at various award shows. Eventually, the stars of the video that received 40 million views received their own regular skit hosting a show within the Ellen show.
Korean-born musical entertainer Psy launched a revolution in the United States when he uploaded his music video "Gangnam Style" to YouTube in 2012. The video quickly exceeded 1 billion views. Psy's controversial political statements about the U.S. combined with the popularity of his song and dance moves at sporting events and clubs rapidly made him a YouTube-generated celebrity.
1 Justin Bieber
Young pop icon Justin Bieber is arguably the most famous YouTube celebrity ever. Musical entertainer and producer Usher boasted of discovering Bieber during his judging role in the spring 2012 season of "The Voice." It was actually music promoter Scooter Braun who first recognized the Ontario-born singer's talents when watching a 2007 video uploaded to YouTube by Bieber's mom, according to "Woman's Day" magazine. Bieber was only 12 when YouTube educated the world on his potential.