I agree with Dave, Doug, et al. This was one of my concerns. I don't think we should join if it means our funds go to freshwater-related events (speakers, auctions). I have nothing against freshwater but frankly I am not interested in it in the slightest and I don't want my membership fee going to anything except marine-related causes.
I think a loosely organized group might be worthwhile solely because it would give us a bit of a pot (which we can't really have without organization because sooner or later someone will walk away with the membership fees or something and we'll be in trouble then) from which to draw if we ever had a chance to get a speaker (if we decide it's even worth the significant costs I expect would be associated with it), or perhaps we could put it towards web hosting. I would be willing to spearhead/assist in the development of an CMAS website, although "society" might not be the best term. (This would of course mean going back and deciding if we have a logo yet*.
) A site could be maintained for under $100/year with more than ample webspace for photos, videos, etc. Money could also be donated to the zoo project if it ever got going. Maybe we could get a nice plaque with our logo on it put next to the tank.
I don't think any formal group we organize should worry too much about holding scheduled meetings. Casual get-togethers seem adequate for our purposes.
* I'll be the first to say I'd love to see the logo I did in use. However I also recognize it may have an unfair advantage as I was able to create it in vector format which is pretty much essential in our case. I would be willing to convert other popular submissions to vector format as well for comparison.