Guestboard - Lead powerfully-organized group events with Guestboard – a modular event platform that gives groups of 10-1000+ people a central space to coordinate, build excitement, and save money. No more crazy email threads. No more massive group texts.

Punchbowl - A party planning and greeting card website

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

RSVPify - A powerful and awesomely customizable platform for selling tickets online for your event.

Mobilizon - A free and federated tool to get our events off Facebook

Online-RSVP.com - Beautiful online RSVP for wedding & other events. Create an online invitation, track your guests responses.