Glympse - Glympse is the easy way to safely share your location in realtime. No sign-up needed.

Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.

OwnTracks - Cross-platform location sharing

Google Groups - Google Groups allows you to create and participate in online forums and email-based groups with a rich experience for community conversations.

Mapple.me - Mapple.me bridges the gap between available time and availability of friends to increase social...

Eventbrite - Discover Great Events or Create Your Own & Sell Tickets