Soccer star Cristiano Ronaldo has launched his own online magazine, the first sports legend in the world to do so. The CR7 eMag, available for tablets and magazines, will feature background stories on him and his friends, as well as Real Madrid, among other things, says Mr. Ronaldo.

Mobio has signed on Portuguese footballer Cristiano Ronaldo as a social media influencer. He is the first addition to Mobio Insider's sports vertical, and will...