Live chat provides the option to interact with visitors to your website in real-time. Banyan Theory websites can integrate with just about any live chat provider. There's no cost to add live chat to your website (other than what your selected provider charges you, which tends to be around $15/month, sometimes per user).
How live chat functions on your website depends a lot on what features are available with the vendor you select. Your Banyan Theory account manager can review your chosen vendor and let you know what is available.