This is huge news: IBM has issued a pledge which allows 500 of their patents to be used in open source software. Not only is this fantastic for open source and a brilliant business move, but it would seem to signal the beginning of the end for software patents. IBM has invested a huge amount in the success of Linux and software patents are probably the biggest threat to Linux's continued growth. At the same time, a large portion of IBM's revenue comes from patent licensing so you'll notice that this isn't a complete rejection of patents.