Over the past 16 years, YouTube has evolved from a video hosting platform to an entire entertainment and social media ecosystem. Its proprietary celebrities—hosts and channels such as PewDiePie, David Dobrik, Mr Beast, Zoella, Miranda Sings, Tana Mongeau, and brothers Logan and Jake Paul—might not carry with them the same level of mainstream name recognition as Hollywood's biggest actors, but to many Millennials and Gen Zs who grew up steeped in a world of personal electronic devices and digital entertainment, these people are megastars.

In fact, many YouTubers have broken out and achieved success and recognition on more traditional platforms: for example, Lilly Singh, who started out as as YouTuber, now hosts a late night talk show on NBC; and Liza Koshy, who achieved fame on Vine before the app was closed down and she launched a career on YouTube, went on to host the pre-show red carpet at the Golden Globes, MTV's TRL, and the revival of Double Dare on Nickelodeon.

However, despite the enormous scale of YouTube and the opportunities it provides its most popular creators, it wasn't until the last few years that we've seen much movement the other way—i.e. traditional mainstream Hollywood celebrities launching individual channels on YouTube. In fact, big names in entertainment are still a little bit thin on the ground on the platform. While some will have their PR teams maintain promotional channels—primarily dedicated to promoting public appearances and upcoming projects—few create and promote custom content designed and produced specifically for YouTube. 

The rise and evolution of social media over the past ten years has created a never-before-possible means for celebrities to interact directly with audiences and fans. Whereas pre-2005, there were very few ways in which a celebrity (or anyone) could build and scale their own creative platform without prohibitive overhead costs, social media and DIY streaming platforms such as YouTube have completely removed barriers to entry, allowing individuals to build their own communities and communicate directly, exactly how they please.

Just this week, model Hailey Bieber and actor Matthew McConaughey launched their own YouTube channels. Bieber's channel will be dedicated to lifestyle videos, conversations with her famous friends, and behind-the-scenes vlogs from her life. McConaughey's is a "destination where I'm going to share who I am and whatnot," he says, as well as life advice. "Hopefully it's going to be all killer, no filler." 

Here are 12 fun YouTube channels to check out, many of which are freshly-launched by some big-name mainstream celebs. Whose channel will you be subscribing to?

Related: Here Are All the Cool New Features Coming to YouTube This Year