I have started out with a Facebook page because it was instant and free. However, I will be investing in a website, as that is what I look for when having treatments myself. I find it it gives me first impressions on if I want to visit that salon. I get a feel for how they want to portray themselves and I see this is their window to the world.
Although saying that, it doesn't put me off if they don't have one and I am going on word of mouth instead. This is very powerful where I live. It's just a shame if they don't have one.
With my Facebook page, I find having a friend who knows everyone, and I mean everyone! helpful to business, in that whenever she has something done I put up photos and tag her in them. Bingo, it generates interest!