Manish Garg: I didn`t get it. How can I optimize for that?
Ammon Johns: Yes, backlinks to the video help it both directly with Google, and indirectly by helping it also rank higher in YouTube`s own algorithm.
The bigger factors within YouTube itself include:
A. The number of full viewings or significant part-viewings - i.e how many selected and watched that video. People abandoning viewing detracts from this significantly.
B. Likes, comments, subscriptions and shares directly via the YouTube interface. Expect this to be weighted to account for how long the account doing these actions has been around, how carefully selective it is about likes and shares, etc. Fake accounts or bought likes will NOT help.
C. The tendency for the video to inspire further viewing of other videos, especially from the same channel.