Well that's a very simple problem to fix, the "-" operator still works, so you can exclude stackoverflow easily, or use the "site:" operator to force the result to come from apple.

You can even setup those parameters as custom search engines in Chrome so you don't have to repeat yourself every time.

True, although I think this is something that I shouldn't have to manually specify.

How would you propose they should differentiate?

Interesting question. One possibility is a heuristic to determine whether the user is looking for a broad overview or trying to solve a specific problem. For example, "2d arrays in Objective C" should bring up a doc page or a tutorial page that provides an overview of the concept; but "How to initialize a 2D array in Objective C" could provide an SO page where someone has asked exactly that. In general, the narrower the query, the more likely it should be that a forum or other UGC site will provide a better answer than an overview page, because someone else has likely run into the problem before.

There are some of us who don't use 'how', 'why', 'where', 'when' as a carry over from the older days when such terms used to just be ignored. So your example would be searched as "initialize 2d array objective-c".