In addition to the action item section, there is a stream/meeting specific action item tab. This pulls out the action items for past and current notes, making it easy to review what has been done, and what still needs to be done.
The action item is to the right of the Stream tab in 1-on-1s, Private Streams, Shared Streams, and Meetings.
This means that during the meeting, you'll be able to review past and current tasks.
You also have the option to sort your action items by a variety of characteristics: Note (the note where the action item was created), Assignee (who has been assigned the task), Due Date (when it is due), and Status (complete, incomplete, won't do)
Depending on how you choose to sort your action item, you'll see different views. The default is Status, which means that you can quickly see what the incomplete action items are from previous meetings (similar to the carry forward function).
And as a final note, the number next to the Action Item tab represents the number of incomplete action items. In this case there are 51: