Yeah, blogs are great for discussing edge cases and the like with people who already know the topic, that books don't have room to cover.
And of course, neither books nor blogs nor language references, etc. substitute for actually sitting down and programming something challenging. But they can help reduce the amount of initial time wasted on trial and error, get you using the language idiomatically, and get you up to speed on language-specific best-practices faster.
Not to mention field reports getting something working - especially useful when an API of a library is not so obvious and the documentation is lacking. EG Rails-centric documentation but using Sinatra.
Although the time could arguably be spent more productively improving said documentation, sometimes an informal tone (which may not be appopriate in docs) can help to dissolve frustrations..
And of course, neither books nor blogs nor language references, etc. substitute for actually sitting down and programming something challenging. But they can help reduce the amount of initial time wasted on trial and error, get you using the language idiomatically, and get you up to speed on language-specific best-practices faster.