We believe the following are instrumental in the spread of Black Hat SEO:
Buying fake Likes, YouTube Subscribers, +1s, etc. from click farms
Spreading hyperlinks that pose a privacy risk
Using a program to automatically follow and unfollow new accounts
Making fake social media marketing profiles to like, share, comment or gather information
Posting artificial negative critiques on competitors pages or positive critiques on your own site
Securing social profiles with rivals names, ranking them in Google, and posting negative comments
These are just a couple of samples of Black Hat social media marketing. But really, there are so many ways you can use social media marketing to positively or adversely impact a company that are outside of the social sites planned purpose.