I think I've found all the classes I've taken either through a message board like here or
www.talkglass.com or on Facebook. The last time I took one nobody was using Instagram, but I see a lot of people using it primarily and some not even using Facebook any more. So I think you're definitely on the right path.
Do you have a web site? A lot of my students find and contact me through my web site.
However I have taught way more classes than I have taken. I think I've taken three. Taught probably 100. Usually they seek me out. Whether it be private classes or a studio wanting me to do a group class (which, by the way, if you want me to come teach in Chicago, just say the word and I'm on the next plane - I LOVE that city).