When Novell signed the deal with Microsoft, it implicitly acknowledged -- whether deliberately or not -- that Linux is 'unclean', that it requires protection from patents. The two deals which followed, namely the ones with Sansung and with Fuji Xerox, seem to indicate that not the kernel is being targetted; rather, it is some related software. Heavily-patented technology such as .Net makes Mono come to mind. The following is a nice video which demonstrates the nightmare one faces when entering the universe of patents.