A second point I forgot to mention is that I do not know of Adobe suing anyone over standard PDF/PostScript features, but there is a long history of Thompson and all the other audio/video patent holders being very litigious and threatening.<p>Perhaps no one remembers 8hz-enc or why the LAME project doesn't distribute binaries (or at least didn't for a long time; I've not looked lately). The story for MP3 players wasn't a super happy one either at one time.