Is Apple worried about Linux or open source communities?

A recent article at silicon.com states that according to Apple's most recent filing with the Securities and Exchange Commision, Apple fears competition from Linux based computers as well as Microsoft. The article is misleading because it mixes the issues of operating system competition with software competition.

Personally I run various flavors of Linux and BSD alongside OS X  at home on my four computers. I use each platform for different tasks. Many power users will tell you that OS X is fantastic for plug and play everyday operation and is by far the friendliest *nix operating system. Perhaps the competition Apple perceives is more in the server market than the personal desktop computing market? Or maybe the silicon.com article is just fodder for a snazzy headline.