There won't be a thing called kpop if there were no 1st gen or 2nd gen ... with the introduction of Seo Taiji & Boys the whole korean music industry saw a new way/light.. since then the building up or foundation of kpop started until the BIG3 were born i.e. SM, YG and JYP... These three literally turn the whole industry to another level.. and YG specially dealing with the hip hop introduction in the mainstream korean music industry.. all group has its own influence or representation in kpop but the introduction of BIGBANG really changed something new in kpop.. like they were ahead of their times.. want proof? then watch their MVs you won't feel like you are watching a music video that was released a decade ago... then for girlgroup its after the debut of SNSD the shaping point of girlgroup and then 2NE1 debuts with their own style that no other girlgroup had done during that time since then the kpop were already taking the international market and audience the only drawback were the use of Social Networking Sites or should i say the digital medias!! were very less during the 2nd generation so the expansion or the domination is not that big or vast comparing to 3rd/4th gen but the foundation of the pathway or the roads were all done by the 2nd gen kpop...