Below is a visualization of the user activity on Biostar since October 2009.
A link to the video:
Users are represented by their names, and the small stars around them are the posts they create. These are color coded by the post type: red for questions, green and blue for answers and comments.
Starting May 2010 we focus on new user activity only. This means that we only show a user's activity approximately within one month after they joined.
For January of 2011, 2012 and 2013 we show the activity by all users. For May 2011 and 2012 we show the moderator activity only.
The visualization is done via the code_swarm tool.