Xbuntu / AMD
Short description of error
No matter what you are doing the number for users for action datablock goes up.
Exact steps for others to reproduce the error
Have a 3d viewport and the action editor open
Select the cube and set a keyframe (this will create a new action datablock for the cube)
Now rotate/move/scale/whatever the cube and look at the number of users using this action datablock
...however if you hit undo (Ctrl+Z) then the number goes back down to what it should be...