UseResponse - Open-source, self-hosted customer feedback software, live chat and helpdesk system that you can install on your server. Organize documentation using knowledge base and get feedback from social networks with centralized system
App for WhatsApp by coldX - Integrated WhatsApp functionality on the Desktop.
UserVoice - UserVoice integrates easy-to-use feedback, helpdesk, and knowledge base management tools in one platform that empowers users to speak and companies to understand.
WhatsGreen Multi Messenger - Easy access to WhatsApp, Line, Telegram, FB Messenger and many others via the Chrome toolbar.
Zendesk - Zendesk is a beautiful, lightweight help-desk solution.
WhatsApp - WhatsApp Messenger: More than 1 billion people in over 180 countries use WhatsApp to stay in touch with friends and family, anytime and anywhere.