"The idea that I can be presented with a problem, set out to logically solve it with the tools at hand, and wind up with a program that could not be legally used because someone else followed the same logical steps some years ago and filed for a patent on it is horrifying." [1]
Whereby this again now is not about the idea but the implementation.
But in many cases, this is also right.
See Amazons 1-Click as an example. I haven't really looked up the implementation details they describe in their patent but I guess it mostly follows the straight-forward implementation of this.
It's worth noting that while the USPTO granted the patent (and even after multiple reexaminations still granted parts of the patent), the patent was never granted at all in Europe: http://en.wikipedia.org/wiki/1-Click#Patent
This applies to ideas too I think - if I have a general 'idea' of how to perform a task, that can be expressed as an algorithm which I then implement in [whatever language]; I could then be unwittingly violating a patent on the idea.
I think John Carmack put it best:-
"The idea that I can be presented with a problem, set out to logically solve it with the tools at hand, and wind up with a program that could not be legally used because someone else followed the same logical steps some years ago and filed for a patent on it is horrifying." [1]
[1]:http://en.wikiquote.org/wiki/John_D._Carmack