To use this plugin you need to have a Jitbit Live Chat account. You can register for a free trial here: http://www.jitbit.com/livechat/trial/ It takes 30 seconds and does not require a credit card.
After the registration, you will get your own live chat URL (https://%your_company_name%.jitbit.com/chat), you will need it to make this plugin work.
Jitbit Live Chat for WordPress loads an external javascript file from Jitbit’s servers. It will execute in your visitors browsers, but don’t worry, the only purpose of the plugin is to create a live chat widget.
Also please note that all communication between your WordPress site and Jitbit servers is secured with SSL.