Sparky writes "We've already heard that SCO have invoked the DMCA via 'letters sent to select Fortune 1000 Linux end users.' The specifics come via a copy of the letter reprinted at LWN.net - they've decided that they own the copyright to about 65 header files contained in Linux - largely errno.h, signal.h and ioctl.h." balloonpup
also notes "CNet News has reported that SCO has reported a fourth quarter loss of $1.6 million, owing mostly to hefty legal fees in its war against Linux. SCO said they would have reported $7.4 million in earnings, if not for the $9 million payout to their lawyers. Way to go, SCO!"
Many readers also point out a Groklaw article indicating Novell has registered for the copyrights on multiple versions of Unix
with the U.S. Copyright Office, so that "both the SCO Group and Novell have registered for UNIX System V copyrights for the same code."