Why Software Patents Are Harmful (PDF)

An excerpt of the paper taken from the "Open..." blog:

"In other industries, research continues up to a point where further research costs too much to be feasible. At this stage, the industry's output merely consists of replacing parts that have worn out.

However, in the software sector, a computer program that is fully debugged will perform its function forever without requiring maintenance or modification. What this means is that unlike socks that wear out, and breakfast cereal that is eaten, a particular software product can be sold to a particular customer at most once. If it is to be sold to that customer again, it must be enhanced with new features and functionality. This inevitably means that even if the industry were to approach maturity, any software company that does not produce new and innovative products will simply run out of customers! Thus, the industry will remain innovative whether or not software patents exist."

http://opendotdotdot.blogspot.com/2008/08/why-software-patents-are-harmful.html