The Lobby Chatwing provides 1 interface for many chatboxes, Read Only channels(Broadcast Mode), and Live Help to all be combined together.
This plugin can make you chat with others who are on your WordPress site now by Ntalker.
This plugin add a widget to show ChatMe.im user login form
Provides a powerful commenting tool to enable comments on specific parts (text/images/videos) of your blog or any web page.
Package for integrating SightMax live chat functionality to WordPress
Live Audio Video and text Chat