Author identification by machine learning - ethics?

I'm working on a personal project involving automated text classification for a variety of purposes, including identifying the author of a sample of text given samples of training text from a very large number of authors.

I'm far from the first to use machine learning algorithms to identify the author of a text, but I think I have something a little better than most of the research projects I've read about and open-source tools I've tested. Initial results show significantly greater accuracy and a couple orders of magnitude more speed in situations involving thousands of possible authors.

I can imagine potentially good uses for this sort of tech, ranging from keeping banned users out of an online community to identifying the author of a ransom note, death threat or the like. I can also imagine evil uses, such as identifying political dissidents to persecute.

I'm not sure how I feel about releasing such a thing in to the world (as open-source or as a product), knowing that it will be used for both good and evil. Any comments?