Good article from ZDnet:
Bill Gates [once said] that software patents had the potential to put the industry at “a complete standstill” and with good reason. If the sort of protection Microsoft now claims for itself had been available to CP/M then, Microsoft would never have created its monopoly, nor amassed a fraction of its power.
Now [that] it has, the rules have changed. Microsoft is perfectly happy, while proclaiming openness and interoperability, to find a company in dire financial straits and then threaten it with expensive legal action over what any self-respecting programmer would identify as a hackish kludge–something that advances the art of computer software not one bit.
(See also the case against software patents.)