Live helper chat main features. I promiss I missed some :D. There is so many features now it's hard to name them all. But we are the most flexible/feature rich open source Live Support System. So your searches are over.

• Multiple chats same time
• XMPP support (IPhone, IPad, IPod, Android, Blackberry, GTalk) basically any device who supports XMPP messages.
• See what users are typing before they send a message.
• Multiple operators
• Send delayed canned messages as it was real user typing
• Chats archive
• Priority queue
• Chats statistic generation, top chats
• Resume chat after user closed chat
• All chats in single window with tabs interface, tabs are remembered before they are closed
• Chat transcript print
• Chat transcript send by mail
• Site widget
• Page embed mode for live support script or widget mode, or standard mode.
• Multilanguage
• Chats transfering
• Departments
• Files upload
• Option to take website screenshot see what user see
• Chat search
• Automatic transfers between departments
• Option to generate JS for different departments
• Option to prefill form fields. 
• Option to add custom form fields. It can be either user variables or hidden fields. Usefull if you are integrating with third party system and want to pass user_id for example.
• Cronjobs
• Callbacks
  • Closed chat callback
  • Unanswered chat callback
• Asynchronous status loading, not blocking site javascript.
• XML, JSON export module
• Option to send transcript to users e-mail
• SMTP support
• HTTPS support
• No third parties cookies dependency
• Previous users chats
• Online users tracking, including geo detection
• GEO detection using three different sources
• Option to configure start chat fields
• Sounds on pending chats and new messages
• Google chrome/Firefox notifications on pending messages.
• Google chrome/Firefox notifications for new messages.
• Browser title blinking then there is pending message.
• Option to limit pro active chat invitation messages based on pending chats.
• Option to configure frequency for pro active chat invitation message. You can set after how many hours for the same user invitation message should be shown again.
• Users blocking
• Posibility to integrate with google analytics event's tracking
• Top performance with enabled cache
• Windows, Linux and Mac native applications.
• Advanced embed code generation with numerous options of includable code.
• Template override system
• Module override system
• Support for custom extensions
• Changeable footer and header content
• Option to send messges to anonymous site visitors,
• Canned messages
• Informing then operator or user is typing.
• Option to see what user is typing before he sends a message
• Canned messages for desktop client
• Voting module
• FAQ module
• Online users map
• Pro active chat invitatio
• Remember me functionality
• Total pageviews tracking
• Total pageviews including previous visits tracking
• Visits tracking, how many times user has been on your page.
• Time spent on site
• Auto responder
• BB Code support. Links recognition. Smiles and few other hidden features :)
• First user visit tracking
• Option for customers mute sounds 
• Option for operators mute messages sounds and new pending chat's sound.
• Option to monitor online operators.
• Option to have different pro active messages for different domains. This can be archieved using different identifiers.
• Dekstop client supports HTTPS
• Protection against spammers using advanced captcha technique without requiring users to enter any captcha code.
• Option for operator set online or offline mode.
• Co-Browsing
• Automatic translations (Bing or Google)
• Desktop client for
  • Windows
  • Linux 
  • Mac
• Flexible permission system:
  • Roles
  • Groups
  • Users
• Powered by
  • PHP
  • eZComponents
  • Bootstrap 3
  • Gulp
  • Webpack
  • Angular 1.x
  • jQuery
  • MySQL
  • QT C++ Framework. - for desktop client
  • http://www.fatcow.com/free-icons
  • http://www.famfamfam.com/lab/icons/
  • https://github.com/niklasvh/html2canvas

For full list of features see documentation section.