While anyone who has spent time on Twitter knows it’s full of automated accounts, a report from the Pew Research Center sheds new light on the degree to which bots dominate the conversation on the social media platform.

According to the Pew study, a whopping 66 percent of tweeted links to the web’s most popular sites are shared by bots. Pew researchers compiled a list of the 2,315 most popular sites and then analyzed 1.2 million tweets that included links to those sites over a six-week period.

“The results illustrate the pervasive role that automated accounts play in disseminating links to a wide range of prominent websites on Twitter,” the report says.

The finding comes as Twitter continues to deal with terrorists, harassment, and hate speech that has turned the service into a cesspool. Meanwhile, the company has been trying to attract new users and gain the confidence of advertisers.

But the bot study is a reminder that a large portion of what happens on Twitter is simply machines talking to machines. The study found that with the bots, 500 of the most active tweet 22 percent of the links to news sites.

One other interesting note: The researchers did not detect a notable political bias in the bots. Instead, the bots mostly seemed to be tweeting at fairly neutral new sites.