This site provides you with general information about threading.

Its recommended to find a threader that Uses Hands Only while threading.

Make sure that the Thread is not placed in Mouth.  Most threaders place thread in mouth.

Are you tired of tweezing your eyebrows hair by hair, trying to get the perfect shape? Do you hate ripping off skin when you wax your upper lip? It may be time to try threading. The hottest trend in facial hair removal has actually been around for centuries. Threading is a common practice in China, the Middle East and India, and the technique is quickly gaining popularity in the Western world. According to Jagruti, the increase in interest and demand for the practice in North America is not surprising since threading is "easy and economical." The process is fast.

Threading is less painful than Waxing or Tweezing.
Threading can be used to shape eyebrows and also remove facial hair.
For example - Chin, Upper Lip, Side Burns