Chatbot site Character.ai is cutting off teenagers from having conversations with virtual characters, after facing intense criticism over the kinds of interactions young people were having with online companions. The platform, founded in 2021, is used by millions to talk to chatbots powered by artificial intelligence (AI). But it is facing several lawsuits in the US from parents, including one over the death of a teenager, with some branding it a " clear and present danger " to young people.