LA Times: All the 'Happy Birthday' song copyright claims are invalid, federal judge rules
XKCD is licensed under a Creative Commons Attribution-NonCommercial 2.5 License.Those who falsely claimed copyright in the words and melody of this song have been extracting $2 million annually from anybody who wants to use it commercially, whether in a movie or on TV, or even singing it to customers in a restaurant. A class action suit is planned to get as much as possible of that money back.This means you're free to copy and share these comics (but not to sell them). More details.