How effective relative to what? Relative to college classes that cost hundreds or thousands of dollars per credit? Relative to high school classes? Relative to self-directed education from books and articles?

I think if there is a problem with MOOCs, it is purely one of expectation. Of course there isn't some magical "if you MOOC it they will learn" effect. Of course people aren't getting hired because of putting a few classes on their resume. But both of these things are true of college education as well. You can't force people to learn, you can only give them the opportunity. Nobody hires on the basis of individual college courses either. It will be interesting to see if the "degree program" equivalents that the MOOCs are trying will be successful, but it's too early to tell.

But ignoring all that, there are now hundreds of opportunities for motivated individuals to learn about an enormous breadth of topics completely for free, with lots of good lecture videos, lecture notes, exercises, projects, and peer discussion. This really can't be anything but a really great thing.