Zendesk - Zendesk is a beautiful, lightweight help-desk solution.
LiveChat - LiveChat - premium live chat software. Approach customers directly on the website, make connections and drive more sales using LiveChat.
HiOperator - HiOperator is a virtual assistant that answers phone calls, chats with customers, provides in-app help, takes orders, and provides support.
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
GetHuman - Find customer service numbers fast
Olark - Real-time chat and monitoring of your website visitors through Google Talk and Jabber.