Also not trying to be a Luddite, but what works for communication between members boils down to what the members are comfortable using. Having to subscribe, join, enter passwords etc. is a completely useless method of replacing face-to-face or even "primitive" methods of communication like the telephone.

A text based/Internet forum seems like a viable method, but, just as "a picture is worth a thousand words," a simple verbal communication by voice transmits about a thousand times the data that a typed input affords in the same amount of time. I just spent eight minutes typing this, whereas I could speak it out loud to you in about 36 seconds. You could respond, I could reply, etc. etc.

Sure, a bulletin board on the Internet is handy, because messages can be reviewed at any time, but, as RAS shows. anonymous and random postings quickly erode the quality of information offered.

You want to set up a quick, easy and directed communication with your members?
Do it with a simple email list. Any member can "Reply" or "Reply All."

Asking your members to subscribe, join, sign a Loyalty Oath or otherwise jump through some ill-defined hoop to remain in touch is counterintuitive and most likely a waste of your time, not to mention theirs.