How to get new, user-content based website from 0-60 - ?

I am building a new site, based on user-generated content.
A very common reaction has been “Well, the site looks great, and it’s
a wonderful concept..I just wish there was more activity.”
What is the best way for me to jumpstart traffic on this site, to get
from 0–60?
I tried burning through friendship capital to get my friends to post
1–4 times each…it burns out fast.
Is it unethical to copy posts from similar sites, or create 5–10
“fake” accounts and post things ourselves/myself?

What would convince you to go to, and actually use reguarly, a brand-new site?

thx