Threads is experimenting with allowing users to sign up using their Facebook accounts instead of solely relying on Instagram accounts. This option, currently under testing and not widely available, is referenced in a Meta support article. The move aims to streamline the sign-up process for individuals without Instagram accounts and potentially influence the personalization of content and advertisements displayed within the app. Meta states that connecting a Facebook account will enable features that work across both Threads and Facebook, including unified login information and data combination for personalized experiences.