Tested with: Blender 2.70a
Currently, the Blender Collada exporter only export the action that is currently active. Other actions are ignored.
This is an issue for game pipelines where assets may have several animations (running, jumping, walking...) created as actions in Blender, but not exported in the Collada file.
The Collada spec supports these animations either as different <animation> in <library_animations>, nested <animation> or <animation_clips>.
Steps to reproduce:
The attached Blender file contains a very simple scene with 2 actions (GoUp and GoLeft) involving a cube. When exported to Collada, only the active action (GoLeft) is exported.