On a video site is it possible to place your own videos to show them to
others. You may also download videos from others. It is often possible to give
comments or to chat on the video sites. That is the treason why they are called
social media.
You may find all kind of videos: about cats, bloopers, humoristic
videos and musiscrecordings.
A special kind of videos are the vlogs. A vlog is is a form of
weblog for which the medium is video. Vlogs handle with all kinds of
subjects: beauty, recipes and menus, manuals a.s.o.
More information:
Wikipedia: video blog.