sitejabber - Check Ratings of Businesses, Read Reviews & Buy

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

Ticketsauce - The #1 White label Solution for Event Ticketing & Marketing

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

Kangaroo Rewards - Maximize sales and customer engagement with Kangaroo Rewards' Customer Loyalty platform. An all-in-one marketing solution that empowers you to reward, communicate, and target your customers to drive growth and deliver a premium customer experience.

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