Backlinks questions!

Hi!
One of the most important things to climb google is the backlink right?
Then load an article related to your niche market on some sites like "ezinearticles" used to create a backlink?
Same goes for youtube?
The greater importance of the site better chance of climbing i think!
Does site like Ezinearticles useful to send traffic or only for backlinks?

Sorry for the english!