Many meetings do not fulfil this function.
Most meetings here in London are chair and discussion meetings. A speaker speaks for a period of time; then the meeting is thrown open to the floor.
I recently visited a meeting with this format. The people were nice, and some literature was read. The open sharing session, however, was catastrophic. A very small number of people in a room of 25 or more had the opportunity to share, because there was no control over the length of sharing. Some individuals shared for over ten minutes.
Typically, those with the most burning desire to share are those who are not applying AA's solution and are consequently extremely disturbed and seeking relief. The only relief available seems to be to convey the details of their emotional disturbance to the room.
During the sharing time, with the exception of one person, no one shared effectively about the nature of alcoholism or the solution. This is in large part due to the format with uncontrolled, unrestricted sharing.
There are several options available. Firstly, the chair or secretary can handpick sharers. Secondly, a chair or secretary can handpick volunteer sharers. Thirdly, a strict time limit of two to three minutes can be applied with some acoustic marker. The waving of a card can be ignored, but everyone knows if a bell has been rung.
My experience is that most meetings without controlled sharing are dominated by those without a solution, and the primary purpose of the group is not achieved. If a large number of individual groups are failing in this purpose, so is the fellowship as a whole.
It is wise, periodically, for a group to ask itself if it is effectively achieving its primary purpose or whether it has become a dumping ground for toxic outpourings and irrelevant ramblings.
Those who need to share to gain emotional relief can likewise do so in many ways before and after the meeting. The unique function of an effective AA meeting can be achieved only in an AA meeting, however. That must take precedence.