By bno – Tokyo Office In September, a significant shift in digital engagement was observed among South Korean users, as American social media giants YouTube and Instagram reported impressive gains in usage, while domestic platforms like KakaoTalk and Naver faltered. According to data from industry tracker Wiseapp, YouTube remained the dominant force, with users spending a staggering 1.8bn hours on the platform last month, marking a 9.5% increase compared to the same period last year, as reported by Yonhap. Instagram also celebrated a notable rise, as its combined usage time soared by 42.1% to …