Tags are keywords that describe videos. For example, a surfing video might be tagged with "surfing," "water," and "waves." Users who enjoy watching surfing videos can then search for any of those terms and that video will show up in their search results. Tags help you find new videos you might like to watch, and also help you label videos you upload so that other people can find them more easily. The larger the tag appears in the list, the more videos use that tag.
To remove one of your videos, simply log in, go to http://www.objectssearch.com/broadcast/my_videos.jsp and click on the 'Remove Video' button next to the video you'd like to remove. You are only able to remove videos that you have uploaded.