A paper by Boston University's James Bessen, "A Generation of Software Patents" takes one through the current state of patents and 20 years of it's journey while introducing you to the ridiculous state of patent affairs. After researching through a generation of software patents, from award of a patent (patent 5,440,676, Alappat) to the expiration of the same, the researcher concludes, that "software patents have 'NOT' provided a net social benefit in the software industry." (a major omission by me 'NOT' was discovered by reader Michael)
Link to the complete paper at the end of the article. Read it and educate yourself.
In 1994, the Court of Appeals for the Federal Circuit decided in In re Alappat that an invention that had a novel software algorithm combined with a trivial physical step was eligible for patent protection. This ruling opened the way for a large scale increase in patenting of software. Alappat and his fellow inventors were granted patent 5,440,676, the patent at issue in the appeal, in 1995. That patent expired in 2008. In other words, we have now experienced a full generation of software patents. The Alappat decision was controversial, not least because the software industry had been highly innovative without patent protection. In fact, there had long been industry opposition to patenting software. Since the 1960s, computer companies opposed patents on software, first, in their input to a report by a presidential commission in 19664 and then in amici briefs to the Supreme Court in Gottschalk v. Benson in 1972 (they later changed their views). Major software firms opposed software patents through the mid-1990s. Perhaps more surprising, software developers themselves have mostly been opposed to patents on software. Surveys of software developers in 1992 and 1996 reported that most were opposed to patents.
A Generation of Software Patents