An external traffic source on YouTube is any link to a YouTube video video that does NOT come from within YouTube itself.

What is an external traffic source on YouTube?

So for example, let’s say you upload a video and now you want to promote it.

You copy the link to the video, and post it to social media.

When someone clicks that link YouTube registers that as a view from an external source.

No one searched for it on YouTube, it didn’t appear on someone’s YouTube home feed, or from your Channel’s page. It came from an outside (external) source.

What counts as an external traffic source on YouTube?

It’s a pretty small list actually:

  • It’s traffic from either websites or apps where your YouTube video is embedded (read more here about how to embed a video).
  • Or it’s if someone came directly to that video’s URL (link) without clicking on anything.
    • They copy/pasted the link into their browser
    • It was bookmarked
    • They’re not logged into YouTube
    • They’re using an unidentified app

Videos embedded on your blog count as external views, because they are literally being viewed externally.

Pro Tip for Embedding Videos on Your Blog – Don’t just embed your YouTube video – add a subscribe button:

If you’re embedding videos on your blog to drive up your blog traffic, throw in a button underneath the video and ask your visitors to subscribe. So you can get a view (if they click to play the video), AND a sub. Just add ?sub_confirmation=1 to the end of your channel page’s link.

This is what happens when the user clicks the button:

Click here to subscribe to my YouTube channel.

Code

https://www.youtube.com/channel/UCm3QCegGbjZ8UkqwTAfjTRg?sub_confirmation=1

Source
Google Support: Discover video traffic sources