So far, about 200,000 people have signed up to become Community Notes contributors "and the waitlist remains open for those who wish to take part in the program," the company's blog post said.
Neil Johnson, a George Washington University physics professor and expert in how misinformation and hate speech spread online, told CNBC in February that a Community Notes program can help provide context for online content, but is not a substitute for "formal fact-checking."
Johnson characterized a Community Notes model as an "imperfect system" that can potentially be exploited by large groups or organizations with their own agendas.