Ticksy - Simple, beautiful customer support.
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
HelpNinja - Simple & Affordable help desk
Outbound Apps by Intercom - Embed apps right inside your messages
Intercom App Store - Integrate with Intercom and grow your business
indemandly - Live chat 2.0: Customer messaging that converts