A video-compilation of various 4-member girl groups has surfaced on the internet, causing quite the stir among netizens. The video features girl groups that debuted as far back as 1998 until recently, including Fin.K.L, 2NE1, Brown Eyed Girls, Secret, & miss A. Put together by a K-pop fan, the video is titled 'The�history of Korea's 4-member girl groups', and the short 3-minute clip was a major hit on sites like Naver, Daum & Youtube, allowing netizens to take a trip down memory lane. Netizens were able to re-visit hit songs by their favorite groups, and it was also easy to see how much K-pop has progressed and evolved over the past 10+ years. Fans were able to also take a look at the early stages of a few stars who are still active in the entertainment scene today, such as�Lee Hyori, Ock Ju Hyun, Sung Yuri, & Ryeowon. Netizens responded to the video with, "I didn't know there were so many 4-member girl groups!", "Please make a video of 5-member girl groups, too!", and "I can't believe its been more than ten years since Fin.K.L debuted." So why are 4-member groups so successful? According to an entertainment insider, agencies tend to pick four-member groups so that each member can take on one of four 'roles': Visual, Dance, Vocal, and all around Entertainer. Check out the video below!