> e.g. using machine learning for handwriting recognition
This is one of the problems with software patents. Using machine learning for handwriting recognition is a pretty obvious "innovation" to anyone with a little background in AI who has thought about the problem at all. If we allow people to patent "using machine learning for X" for all activities X, that blocks a lot of innovation. The field is moving so fast right now that people are thinking of new ideas all the time; we don't need patents to encourage that.
There are some non-obvious algorithms that are worthy of patenting (that is, if algorithms were actually patentable). One that comes to mind is the fast inverse square root algorithm (https://secure.wikimedia.org/wikipedia/en/wiki/Fast_inverse_...). In our field, trade secret (e.g. compiled source code) is usually sufficient to provide protection against a competitor stealing a novel algorithm, rendering patents largely unnecessary.
http://en.wikipedia.org/wiki/Patentable_subject_matter#The_a...