The purpose of having a sponsor

• [like to a therapist] It provides someone who you can be totally honest and open with. If you share ABSOLUTELY EVERYTHING during a meeting, then the information WILL find its way outside the walls. You can't discuss particularly salacious stuff with the larger group.
  • Things that you did that are potentially illegal, and that happened recently, is one clear category... There's a good chance that SOMEONE listening will pass that info on to the police.
• they're someone you can call on the phone, and they often will promise to respond at a moment's notice, in case you're in a situation where you fear you're on the verge of acting out
• other external links: [1]
  pp24-25

The purpose of doing a "share", especially one without crosstalk

• mutual sharing of problems
• self-disclosure — it's a way to reduce unpleasant emotions such as pain, fear, loneliness, nervousness and low self-esteem — these are risk factors, if kept bottled inside, for acting out
• reasons why crosstalk is avoided: [1] [2] [3] [4]

Interesting writeups about the purpose of several different things, or of the meetings overall

• [1] [2] [3]