Categories are a helping feature of videos on YouTube. Every time you upload/update videos, you have a choice of selectable categories, such as Music, Gaming, Comedy, Lifestyle (People & Blogs), Education, Entertainment, Sports, Autos & Vehicles, News & Politics and Pets & Animals. Each YouTuber has a different category for their channels. Most are related to People and Blogs (Vlogging), Gaming, Music, Comedy and Entertainment.
Each category has its own separate YouTube channel, and all of their channel names have a "#" right before the name (for example, #Music). These YouTube channels are different, as they do not upload their own content. Instead, these channels are YouTube spotlights, which feature popular videos related to their category.