Requests--When you need something from another person at the table. Your request should be clear and precise, notes Comaford. Avoid the vague ("Can you get me info on our top advertisers?") in favor of the specific ("Can you get me a report of our top 50 advertisers in the USA with spending history for the current + past 5 years in a spreadsheet by 4pm this Friday?")
Promises--The commitment, by a person or persons at the table, to fulfill a request. This is why specificity is important; it gives the promiser a deadline and a detailed deliverable. It's the job of the meeting leader to record all requests and promises. After the meeting, the leader shares her summary with the group, so there is a single record of deliverables and a timetable for executing them.
The three that are ineffective, but still happen too frequently: Info Sharing, Sharing Oneself, and Debating/Decision Making/Point Proving -- Too often, participants waste time with what could've been relayed via e-mail, social networks, or water-cooler conversation. Debating and sharing can be fruitful activities, but a meeting is the wrong setting. "The goal isn't to solve detailed problems in the meeting," notes Comaford. "It's to assign responsibilities based on requests and promises made."