Pete,

It sounds like a wonderful idea. A centralized 'swap meet' concept sounds good.

I would suggest that buy and sell listings have an 'expiration date'. People would have to relist their entries to keep them on your board. I know I have had the experience of contacting folks who have listed their interests on rosters (such as on the CCGTCC site) and they never update their entries. I have ended up writing to invalid email addresses and wasting time contacting some who have changed their areas of interest and no longer collect what they originally said they did.

Best,

Steve in Albuquerque