Observer is @3rdEden's entry for the Node Knockout 2011 contest. It's a 48 hour coding competition where you have to build a web application build upon the Node.js web stack
You sign up for the service, and place one single script at the bottom of your page. The observer.js script will establish a real time connection with our server and stream the events to our database (note no private information is logged). You can than login in to the back end of the script and start following / observing your users in real time.