In some cases, patents can be exceptionally powerful and constrain how everyone uses the Web. Unisys, for instance, owns a patent on a method for compressing data that is incorporated into the GIF image format. In recent years, the company has been trying to enforce the patent - which potentially affects everything from Web browsers to Web sites that use GIF images. Traditional patent licenses, which are negotiated between corporations, often return a percentage of the fee to the inventor. But royalty agreements like these just aren't compatible with a system that requires everyone to share their source code freely.
Some companies avoid payments by swapping patents.
However, the wide-open cooperation of free software development makes it difficult, if not impossible, for the community to generate its own patents, says Eben Moglen, a law professor at Columbia University and the volunteer general counsel at the Free Software Foundation. The organization is responsible for the creation of the Gnu Public License. Richard Stallman, one of the intellectual leaders of the open source movement, has been trying to organize a patent pool that would operate similarly to the Gnu Public License. If you used patented ideas from the pool, you would need to contribute your own patents to the pool. This system would draw in more and more patents, he says - but only if it had good enough bait at the beginning.