For IBM Connections 5.5 and IBM Connections 6.0:
There are some applications which add items to the "Action Required" activity stream like:
Now, in my tests, the only action which gets removed from "Action Required" is community invitation, e.g. if the user accept the invite in the communities view "I'm invited".
If an user (or activity owner) marks a TODO item as completed or the activity as finished, the TODO item is still listed in the "Action Required" list.
If an user (or another reviewer) has approved or declined a document inside library, the corresponding action is still listed in the "Action Required" list.
The user has to clean-up the "Action Required" list on his own ... each item one-by-one.
Enhancement request: Whenever a task is finished, the "Action Required" list should be updated and the corresponding action item being removed.