The main problem with video files, and images too, is that they are basically invisible to search engines. The video is a big digital file that the search engine cannot see. It cannot crawl through the narration, it cannot hear the audio, and it does not recognize any of the images. The metadata attached to the video IS accessible to the search engines and this is the information the search engine uses to tell what the video is about. So this is your golden opportunity to tell the search engine what the video is about and to tell potential viewers why they should watch your video.
The reason you want to add keyword rich metadata to your video file is to make it easier for search engines, including YouTube’s search engine, to find, categorize and list your content. In this respect keyword best-practices for websites and blogs applies to videos as well.
For example if you have a video about motorcycles using the keyword “motorcycle” will not help. Motorcycle is a common word and it is found in a lot of content and videos. Using keywords such as “Harley-Davidson,” and “soft-tail motorcycles” or “Motorcycle tours,” “Oregon” are more specific. How general or how specific you get is a balancing act. A lot of people may search for “Motorcycle” but there is a lot of content and you may not show up in the search. Far fewer people will search for motorcycle tours in Oregon but when they do you will show up. In this case you would use your keywords like this:
Title: Motorcycle Tours in Eastern Oregon Video
Description: A video about popular motorcycle tours in Eastern Oregon. Get a motorcycle rider’s view of Eastern Oregon with an HD camera mounted on a Harley-Davidson soft-tail.
Tags and Keywords: motorcycle Oregon tours “motorcycle tours” “Eastern Oregon” “Oregon Motorcycle Tours” “Harley-Davidson” “soft-tail” (in YouTube a single word is a tag, a group of words within quotes is a keyword or keyword phrase.)
For an easy to follow guide on how to edit the metadata for your YouTube video download the free E-Book: Search Engine Optimization for YouTube Videos.