Unionized workers of Kakao Corp., South Korea's messenger app operator, took a day off en masse on Monday in a sign of protest amid a continued gridlock in wage negotiations. In their second collective action, unionized members staged what they called a "Log-out Day" by taking simultaneous annual leave. Some 2,100 workers from five units of Kakao, including its headquarters, Kakao Pay and Kakao Enterprise, have participated, the labor union claimed. The company, however, said it estimates only