Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
CooMeet - CooMeet is one of the best and leading next generation of video dating web-based application specially designed for those users who want to talk online to people they have never met.
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Openki - Platform where you can search, propose, take part, help organize or publish workshops, lectures...
Google Groups - Google Groups allows you to create and participate in online forums and email-based groups with a rich experience for community conversations.
Hinge - Find people you want to date through your friends on Facebook.