What is a Meeting Parking Lot?
A meeting parking lot helps keep track of important items that may not be useful to discuss in the current meeting. As subjects come up that don't relate directly to the topic under discussion, they are added to the group's parking lot.
The parking lot should be reviewed as part of closing the meeting. For each item on the parking lot, the leader checks whether the topic still needs to be discussed. If not, the item is removed. If the group feels it does need to be addressed, they either decide to extend the meeting and deal with it or create an action item assigning someone to schedule a follow-up meeting on that topic.
The parking lot goes by many names. For instance, one group calls this list the "cooler" and others put items on the meeting backlog (used for grooming topics for future meetings).
An interesting take on the concept is to phrase parking lot items as "Great Idea. Different Meeting," which acknowledges the value of the item and naturally leads to a discussion about "at which future meeting will we discuss this?"