In Chiang Mai there are meetings (monthly, I believe) and there are breakfasts (twice monthly.)
The meetings are where club business is discussed (finances, events, guest speakers, etc.) It's a more structured event than the breakfasts and - personally speaking - I can't imagine it would be of interest for a first time visitor unless you were planning to be a participating member long term.
The breakfasts are purely social so you show up, check-in, pay, then head for the buffet line. Take your plate, choose a group of people with whom to sit, eat and discuss whatever comes up. Pretty casual and this is where I would suggest one begin as a new visitor.
Nationality mix: Americans, Western Europeans, Australians, Japanese mostly.
(Disclaimer: I haven't attended in about five years. What I have described above may not be accurate today.)