There is Korean website I've known about for the past 10+ years - MissyUSA
It is a Alexa ~ 35,000 global site:
http://www.alexa.com/siteinfo/missyusa.com
So it is not all that large. They have had a women only policy and focus on Koreans in the US - it is pretty active and is has a political impact:
http://www.koreatimes.co.kr/www/news/opinon/2013/05/390_1357...