When you upload a video directly to Facebook, it gives you the option of adding video tags. These can be specific, like the name of the band, or general, like the style of music being played. To be honest, I have not found any evidence that these tags do anything. I have done searches in Facebook for the tags I have used that were not part of the video title or accompanying text. The videos I put the tags with never come up in search results, even videos that have been shared by people hundreds of times.