exploration on marketing the intrinsical interest

A friend is marketing his new brand of therapy. This makes me wonder how to reach intrinsically interested audiences. So I search for an article about fingernails and targetting audience. This is because I heard once that a certain group in Amsterdam targets people who have clean fingernails because they are more often open for therapy. Maybe they don't tend a garden? I'm finding not much of use, not the reason why the fingernails have to be neat. The closest I came to have my question answered was from Yahoo: why do we have nails and toenails?
Later on the day I reflect on my blog. Sometimes I try out some marketting strategy that I read about to realize that what I wrote that day doesn't match the new audience I reached. I shouldn't be playing, but planning. To return to one of my interests, learning through playing.