You could argue that it's not very different at all. And it also overlaps significantly in some areas (particularly statistical machine learning) with http://stats.stackexchange.com/

Not that that's a bad thing. Competition is good, and the difference may evolve to be nothing more than culture, or focus or whatever. I mean, HN is similar to certain reddit sub-reddits (or combinations thereof) such as /r/programming and /r/startups. But there's room for both. Same deal, IMO, with AI / Machine Learning / Data Mining / etc. related Q&A sites.

Oh, and never mind that there are multiple subreddits devoted to these topics as well! /r/machinelearning, /r/artificial, /r/sysor, etc. jump to mind.

Let the market sort it out.