Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Padlet - Visual boards for organizing anything.
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Snapchat - Real-time picture chatting
Bylde - Bylde is a SaaS platform you can use to Start, Manage and Grow your groups and communities.
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.