[James Harries]"Of course but the platform is also an important factor I think."
Unless the platform is refusing to play videos you upload, it is not an important factor at all. YouTube can work just as well as Vimeo or Wistia or any other. If you don't drive traffic to the content you want to be seen, the platform is a big fat zero in factoring in.
[James Harries]"Any guidelines on how to drive traffic to the video?"
You have to figure out how to get it in front of eyeballs. Most people just spam their Twitter/Facebook feeds and, unless you're someone who has a ton of involved followers (like a celebrity) that usually doesn't do anything. It's take finesse and time investment in communities.