When I was leveling my first-ever shadow priest, I instinctively took the tailoring as one of my two main professions. I did it because I was leveling a cloth-wearing class and thought it'd be easier if I could make my gear. It never really occurred to me that I could actually make money through tailoring.
Of course, after exploring the auction house and learning more about my server's economy, I realized that I could make money with tailoring -- and in a number of different ways, to boot. It wasn't easy money, to be sure; tailoring had a lot of weird quirks that made making a lot of money challenging. It doesn't help that there are plenty of tailoring items being listed on the auction house at a price well below the material cost, either.