You mean like a Sybil Attack? You might be right about a certain culture of sockpuppetry on places like Reddit where it's actually trivial to setup multiple accounts under different IPs and then upvote all your stuff. It's no secret you can pay for services where people do this for you and 'astroturf' your chosen topic and make it seem more popular than it actually is.
https://en.wikipedia.org/wiki/Sybil_attack
https://np.reddit.com/r/shills/comments/4kdq7n/astroturfing_...