Threading is primarily an Asian technique that seems to be catching on here in the States now. The technician uses a thread looped somehow to pull out the hairs. Sorry I can't be more descriptive, but I've only had it done once and my eyes were closed, so I couldn't see the process. It hurt a little less than waxing. Supposedly, the hair won't grow back as quickly, but I found that not to be true. Another benefit of threading vs. waxing is that it's not as rough on the skin. I had no redness afterward.
Threading might be the best way to go for a young person who hasn't had her eyebrows done before. Less painful and possibly less intimidating.
Just my $.02
sk8belle