You've also got to think about socio-economic class. It's not such a good idea to put ads for theatre shows up in notice boards in working class suburbs. I don't want to sound like a snob, but it's just a fact that people from suburbs like Balga don't go to stage shows as often as those from Subiaco and similar areas.
That's why anyone who caters for the more alternative set should use noticeboards down in Fremantle. If you're promoting things like yoga classes, mediation, health, diet, or anything vaguely New Age there are a lot of people in your demographic. There's one massive noticeboard at the Fremantle Library that would get a lot of people in your target demographic looking at your ads. There's also one outside a New Age store called the Blue Buddha in the Manning Arcade nearby. There's another one in a shop in South Terrace. I'm pretty sure it's Manna Health Foods, on the corner of Nelson St.