A plug-in browser extension that alerts users to unreliable news sources on platforms and outlets, like Facebook, Twitter, and Google. It can be added to Google Chrome and Mozilla browsers. It uses lists of fake news sources as its references to determine what information is accurate and what is fake. When it identifies a story that is potentially false, it flags it with a red banner and presents the message "This website is considered a questionable source." Technologist Daniel Sieradski created the B.S.