The Heartbeat module displays user activity on a website. This module functions as an API to log activity. The logged data contains message structures, attributes and variables. Once the activity messages exist in the database, they will be parsed and build into activity streams.
Other modules that work great with heartbeat activity
There is a test/demo site running at Menhireffect. This is currently under development as well and will updated frequently. It is always running in the latest version.
Enable the debug mode setting when you want to know in detail why certain fetched messages aren't shown.