Public - Group chats.
Two Factor Auth (2FA) - List of websites and whether or not they support 2FA
nocnoc - Instant group chat invite via link
X (Twitter) - Connect with your friends and other fascinating people. Get in-the-moment updates on the things that interest you. And watch events unfold, in real time, from every angle.
Viber Communities - Group chat with up to 1B members, admin controls and more
Rapid 2FA - A painless way to add two-factor authentication to your site