Seed smartly. So put it where you're most likely to find the right demographic.
Think deep, not wide. Successful campaigns don't distribute their clips to 50 networks at once. Just because you upload it to a site doesn't mean everyone will see it; instead select 3 to 5, buy media to support it, reach out to targeted press and users and aim to climb that "most watched" list at a handful of sites.
Don't spell it all out. From a creative standpoint, you want to leave room for interpretation. Look at Microsoft's Jerry Seinfeld- and Bill Gates-starring "I'm a PC" campaign or Cadbury's "Gorilla" ad. Successful online videos keep people guessing.
