"All they can do is try to get money from Linux users by guaranteeing them that if they pay now, they will be compliant and avoid the headache of litigation down the line," Carey said. "But, given the licensing conditions of the GNU General Public License, which governs Linux and does not allow royalty or license payments, any such move is also likely to be strongly contested." Blake Stowell, director of communications at SCO, declined to comment on the licensing possibility but confirmed the company had received feedback to the letter it sent warning that Linux is an unauthorized derivative of Unix.Many CEOs who received the letter asked SCO for guidance on how they could become compliant. "We are in the process right now of considering what they could do to come into compliance," Stowell said. Asked by eWEEK if a fee is a possibility, Stowell said that it "could be."Bradley Kuhn, executive director of the Free Software Foundation, in Boston, said that any licensing, royalty or other fees charged to Linux users would not be in compliance with the GNU General Public License. If a company agreed to pay royalties to SCO, the FSF would be hostile to that notion and would probably sue to enjoin it, Carey said. "From a free-software and open-source perspective, what SCO is trying to do looks a lot like extortion because they believe SCO has no rights to the Linux code and may now be preparing to charge people for its use," he said. Linux users also will not get clarity from the courts soon. SCOs Stowell said the Utah court is not scheduled to hear the companys application for a permanent injunction to stop IBM from shipping AIX until 2005. Carey said this indicates that SCOs strategy is to let "the pot simmer for years and let people get increasingly worried about the legal risk."