What criteria does YouTube go by for results?

  • Does the number of subscribers play in this formula/algo?
  • Is YT able to scour the audio itself for keywords/phrases?
  • Does a strong linked-to site help?
  • Do links from a site to YouTube help?
  • Do sites hosted by YT have a preference over those privately served?

BTW - I did an Advanced search here "YouTube rankings" and was surprised to find no one else has questioned this, apparantly.