The Samwer brothers are at it again. Shortly after cashing in on Citydeal , Germany's most prolific startup investors have put millions into Panfu . Their incubator Rocket Internet joined by Holtzbrinck Ventures has invested a rumored seven digit Euro sum in the multi-language educational gaming world for kids. It's their third joint investment in Panfu, former rounds were done together alongside other investors. Since its launch in December 2007, Panfu has become Europe's leading website for kids between 6 and 14 years with nearly 13 million registered users and has been profitable since early 2009.