indemandly - Live chat 2.0: Customer messaging that converts
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
Freshdesk - Freshdesk is a cloud-based customer support software that lets you support customers through traditional channels like phone and email, social channels like Facebook and Twitter, and your own branded community
Intercom App Store - Integrate with Intercom and grow your business
Zoho Desk - Industry's first context-aware Helpdesk Software
Chat Center - Chat with one click, no matter what messaging app you use