Many (probably most) computer programmers favor elimination of patents that apply to software. I believe, as is often the case, that they're well on their way to repeating a dark history they've blithely ignored.
Patents were invented as a service to society -- the basic intent was (and remains) fairly simple: give an inventor exclusive rights to his/her invention for some limited period of time in exchange for agreeing that as soon as that limited period of time expires, the invention goes into the public domain -- anybody can freely use it. By itself, that wouldn't mean much: after all, if the patent didn't exist to start with, anybody would be able to make free use of the invention immediately, instead of waiting for the patent to expire.
The benefit to society comes from another requirement for a patent: that the patent describe the invention so others can use it. The exact phrasing varies by country, but in the US the requirement is that the patent contain a description of the invention sufficient for a person of ordinary skill in the art to implement the patented invention.
Going a step beyond that, US patent law also includes a "best mode" clause that says the inventor must reveal what he believes to be the best method of implementing/deploying/using the invention. For example, if he's thought up a new type of oil for lubricating automobile engines, he can't patent it, but in the patent claim that it's intended to be used as cooking oil (which could deprive society of the benefit, because they ignore it after finding that it makes food taste terrible). Obviously the example of a cooking vs. lubricating oil is a bit extreme, and probably easily seen through -- most people would probably think something was a bit odd about Exxon patenting what they claimed was a cooking oil, for example.
Anyway, let's take at least a quick glance at that dark history they're ignoring. Before patents were invented, most crafts were governed by guilds. To learn how to carry out a particular craft, you had to be admitted into the proper guild. The guild guarded the secrets of its craft quite carefully in most cases -- to the point of sometimes murdering people who were suspected of revealing guild secrets, and refusing admittance to others because they were seen as too dangerous. In other cases, there were literally wars between competing guilds. These not only get people killed, but in some cases when a guild was destroyed, its secrets died with it. Archaeologists have found artifacts showing techniques we don't quite know how to duplicate to this day.
As many problems as they had, guilds were a substantial improvement over the previous system: one of individual craftsmen keeping secrets entirely to themselves, to be passed onto their children, sometimes on their deathbed -- or taking their secrets to the grave, if their children weren't handy at the right time, or were estranged, etc.
Most arguments programmers level against this fall into three broad groups. The first is that programming techniques (algorithms, protocols, etc.) get published even when there are no patents. The second is rarely quite so clearly articulated, but basically comes down to the notion that if one person invented something, they can invent something at least equally good when and if they need to. The third is that software moves so quickly that by the time a patent has expired, it's no longer of any value.
The first is partly true. They can point, for example, to the fact that European companies continue to publish despite the European policy against software patents. This, however, ignores reality. What's happening right now is that Europe is basically "freeloading" off of the patent systems of other countries (US, Japan, etc.) If, for example, Seimens or Philips wants a patent in the US and/or Japan, they need to publish all the details of that invention in their US/Japanese patent application. That means the invention is no longer secret -- and given current communications, the minor detail that it's published in the US/Japan instead of somewhere in Europe adds (at most) a few milliseconds for a European citizen to download the patent application. As such, Europeans enjoy the benefit of inventions being published, without (themselves) giving the inventor anything in return.
The second strikes me as simple conceit. Yes, there are patents running the gamut from utter stupidity to simply being something nobody else thought was important or original enough to bother patenting. Being at all honest, those constitute only a fairly small percentage of patents overall though. Much of this stems from a problem I've seen many times: somebody will draw a badly mistaken conclusion about what the patent covers, often based on looking at nothing other than the patent's title. They see a title that says something like "A method for run-length compression", and they think something like "good lord what insanity -- everybody's known about RLE for ages -- obviously the patent office is a bunch of idiots!" Though it's barely possible they're (at least sort of) correct, and this really is a patent on something everybody's known about for decades, chances are it's something else entirely -- some (possibly minor) improvement that allows the job to be done a little faster, or using a little less memory, etc. In a typical case, it's not earth-shaking, but is original and at least mildly useful.
The third argument may sometimes have some degree of validity as well, but often doesn't. This argument, however, ignores that fact that if the invention becomes obsolete quickly, the cost of the patent (to the people) is also low -- if an invention is only meaningful for a year or two, the cost to society of the fact that an inventor (theoretically) gets exclusive use of it for years afterwards costs society essentially nothing. At the same time, people have invented and patented algorithms that retain value well after the patent expires. An obvious case in point would be RSA encryption. The US patent on RSA expired well over a decade ago, but it's still almost certainly the most widely used from of PK cryptography. RSA remains (roughly) as valuable today as ever, although there are alternatives that could be used if RSA were not available.
Now, don't get me wrong: I don't think the US patent system (or probably any other) is anywhere close to perfect. Some time soon, I'll write a post about what I see as problems in the system, and at least some ideas about how to fix those problems. To give fair warning: I believe many of the problems can be fixed with much less drastic changes than most people seem to think are necessary. In fact, some of the changes are (or at least initially seem) so minor that they're probably almost invisible except to attorneys who specialize in intellectual property law. Nonetheless, I think some seemingly trivial modifications can have fairly serious consequences.