i've seen them on fox news. i've seen them on the local news around my area. >> reporter: there is a ton of social media platforms. >> yeah. >> reporter: why are we talking about facebook here? >> well, facebook has the biggest reach. and i think presents one of the biggest challenges. this challenge isn't for the democratic party. this challenge is for american democracy. >> reporter: katie paul tracks extremism online. >> what facebook should be doing right now is the exact same thing it should've been doing a year ago and two years before that, ensuring this content is not easily accessible on the platform. >> reporter: facebook did take down some of the posts that were flagged by the dnc and the biden campaign. facebook declined an on-camera interview for this story, but facebook's spokesperson andy stone told cnn we've done more than any other internet company to combat harmful content including limiting content that saw to delegitimize the outcome of the election both before and