I think each of the three sites listed has a slightly different focus. Slashdot has a wide "nerd" focus, from computers to astronomy, and typically seems to fol

I think each of the three sites listed has a slightly different focus. Slashdot has a wide "nerd" focus, from computers to astronomy, and typically seems to follow major industry happenings. HN is focused on the boot strapping entrepreneur-hacker. programming.reddit seems more interested in actual programming, techniques, languages, etc. Sure, they all overlap the same general market, but each one caters to a different niche. I think as more communities pop up, catering to more and more niches, we'll notice less 14 year olds because they will be spread more thinly, but they'll still be there.