Anybody have experience in social media/online advertising?

Hey makers! Overlooked is a platform dedicated to combating misinformation in the news. We write and sell access to algorithms designed to do this, as well as host the safest place for you to tag your friends in articles and start a discussion (overlooked.com if you want to check it out). Basically, our algorithms read articles and give back a score out of 100. The more biased, the lower the score, which allows users to understand if the articles they read are opinion pieces or not. We also allow users to rate an article's political affiliation on a scale from far left to far right. As of now, we have been growing at a moderate rate using twitter, facebook, and Instagram. Twitter, however, is becoming harder and harder to advertise on, leading to a setback in our growth. Other than paid ads, does anyone have ideas for successful promotion techniques? Thanks and let me know what you think!