Actually the mix has stayed fairly steady over the years. If anything the technical posts have upticked a bit. Sometimes when this comes up I pick a random date and look in the Internet Archive for the front page that day to see what sort of differences leap out. Maybe I'll do that again.

Edit: ok, I randomly went to http://web.archive.org/web/20120823000341/http://news.ycombi..., which makes the point clearly, maybe too clearly—it almost seems like too strong an example the other way.