Live chat software - Realtime visitor stats.
Not only do you get the normal visitor tracking function, You can also see exactly when a user visits your site.
The admin console will tell you exactly how many seconds ago someone landed on your page.This is a great way to get ready for a chat. ( if that user decides to use the chat )
You also get a full breakdown of who has visited your site, where they came from, what page they landed on and if they chose to
chat to you.