1. IBM porting Red Hat Linux to run on IBM mainframe hardware made it viable to run Linux on mission critical applications.
2. Android--the world's most prominent cellphone operating system--runs on the Linux kernel. (Note Apple's iOS and MacOS X runs on the Mach kernel--one that was originally refined by NeXT in the late 1980's to middle 1990's.)
Actually, I think OSX is a BSD derivative. I don't think it's Mach. Sword would know.