http://www.blender.org/api/blender_python_api_current/ As of 10/11 november 2015 we can now link to the current api docs and not be worr...
May 28, 2011
Action Data - How to purge
Running a large section of CSV data as a simulation i was getting 6 megabyte worth of action data, and i didn't want to save those keyframes in the file, couldn't figure out how to purge the action data from the .blend, ideasman_42 offered a solution.
for a in bpy.data.actions: a.user_clear() # save and reload