A colleague and I were involved in setting up a pretty nifty calculation engine for an ex-employer of mine (a recently defunct ERP vendor). At the end of a lot of sweat it worked brilliantly, so much so that we were asked to submit a patent. At which I expressed a distinct lack of interest - most of our inspiration was good old fashioned software design, lots of iterations, with a fair dash of I've-seen-this-before as smart software practice. My colleague went along, more out of duty than anything else and we may have ended up with a patent.
I don't mind patents, including possibly software patents, but I really could not see anything we did that was justified "defending our rights" after having gotten ideas from the mainstream programming community at large. 4K/yr patents of "original thinking"? Yeah, right.