How can a video be judged to be successful?

A vide can be judged to be successful in many ways. One of the ways is by putting the video on youtube, the more views and likes you get this shows if the video was a success. Another way is by checking how many sales the video has and if there has been an increase the sales- CD/Download. Another way a video can be judged is a positive word of mouth also good reviews in magazines, newspapers etc.