Paul Bradshaw‘s online video checklist:

• Short
• Illustrates something that couldn’t be described as well in words alone (by most people)
• No anchor – in fact, no commentary at all
• It runs alongside, and complements, a text-based article, rather than replacing it.
• Compelling content (i.e. cute animals)

This was given as part of a comment on “You chance to name leopard cubs.”

He also said

It reminds me of the moving images on newspapers in Harry Potter films – perhaps we need to think of video in those terms, though not always.