Nowadays, it's pretty common for social media influencers to break into true celebrity status (and for bona fide celebrities to hit peak influencer status). But back in the day when social media was still pretty new, it was a much rarer case.
Nowadays, there are a lot of celebrities who got their start on apps and platforms. In a lot of cases, like with the celebs here, you probably forgot about their YouTube covers and Myspace pages.