But there was a problem: someone else had independently invented a similar concept in 1994, and held a patent on the process. Through a "gentleman's agreement," the patent holder agreed not to pursue litigation against rsync.
In 1999, a new idea based on the rsync algorithm was ripe for implementation: RProxy. It held the promise of reducing web browser traffic by as much as 85%, alleviating a lot of frustration among dialup users of the time, as well as being useful today in much of the developing world. There was one problem: the 1994 patent. Because of this patent, RProxy never saw the light of day.
Perhaps this is no big loss. Perhaps RProxy would have had little, if any, impact. But we'll never know. The free market never got to decide. Maybe one day RProxy will be resurrected, but if it is to hope to avoid patent infringement claims, it must wait until at least 2014 to do so.
Do you know of other free (or proprietary) software that was killed by murky patent claims? We often hear of big companies like RIM and Microsoft running afoul of patent trolls, but the press seems less interested in the story of the little guy, whose innovations were smothered by the massive weight of hundreds of thousands of patents granted each year. What software don't we have today, because of the patent system?