South Korea's Kakao Pushes Boundaries of Social Media

BARCELONA—Jan Koum, WhatsApp Inc.'s chief executive, vowed this week to keep his messaging service simple, despite a $19 billion deal to be swallowed up by Facebook Inc.

Sirgoo Lee, co-chief executive of South Korea's Kakao Corp., is making no such promises. With 133 million registered users, Mr. Lee is rolling out dozens of services—from basic messaging, mobile gaming, Instagram-style photo sharing, and online shopping—all on a...