I tested this out on Facebook.

I asked people who see the post to like it.

The result was rather interesting, because of the 10 people who liked it (I usually get more) the vast majority were people who rarely like what I post, and the people who usually like my stuff, apparently didn't see it. I even asked a few friends who I engage with a lot on Facebook.

Interesting.

Made a post about it here: https://steemit.com/steemit/@schattenjaeger/i-ran-a-test-on-facebook-to-see-how-much-visibility-a-steemit-link-gets-and-the-result-was-interesting