유명하다 be famous. Ex) he is a famous actor. 인기를 끌다 catch popularity Ex) the actor catches popularity these days. 인기가 많다. Be popular, have many popularity Ex) he is the most popular man in the school. 유행하다 Be in now, be in hot, getting popular Ex) the song is getting popular now, this style is in now. Four of them are similar but has a little bit different meaning. For more information, contact me ^^