YouTube does actually have video categories that the uploader selects, although historically it has led to people mis-categorizing their videos on purpose.
For example, before gaming was a category that was embraced by YouTube, many popular gaming creators would categorize their videos under Comedy instead of Gaming, because the Gaming category did not have a spot on the front page. This also led to a fights between gaming YouTubers over mis-labelling under lesser used categories just to get the top spot and end up on the front page.
As far as I can tell the categories are as follows: Autos and Vehicles, Comedy, Education, Film & Animation, Gaming, Howto & Style, Music, News & Politics, Nonprofits & Activism, People & Blogs, Pets & Animals, Science & Technology, Sports, Travel & Events.
For example, before gaming was a category that was embraced by YouTube, many popular gaming creators would categorize their videos under Comedy instead of Gaming, because the Gaming category did not have a spot on the front page. This also led to a fights between gaming YouTubers over mis-labelling under lesser used categories just to get the top spot and end up on the front page.
As far as I can tell the categories are as follows: Autos and Vehicles, Comedy, Education, Film & Animation, Gaming, Howto & Style, Music, News & Politics, Nonprofits & Activism, People & Blogs, Pets & Animals, Science & Technology, Sports, Travel & Events.