I tried posting on Reddit about our campaign and it only got comments from myself and one other redditor. I've actually gotten to the front page more than once before but it's definitely hit or miss
You submit a link or post and hope it receives attention. If you keep commenting by yourself or submitting the same link in the same day it will be considered spam. It really is random with reddit. Sometimes you'll get a few upvotes, maybe a comment, who knows.
I read this article a while back (sorry for late reply). But I just wanted to personally thank you for wonderful tips! We've put it to good use to grow our subreddit's (/r/shapeit) subscription numbers!