"Of course, there is plenty that dictionaries still do well. Online dictionaries provide most of the definition links that pop up in Google. Dictionaries are still good for obscure usages and etymologies. Dictionaries also can arbitrate disputes that arise during a game of Scrabble or late-night conversations.
But dictionaries have also failed us in many ways. They infuriate word sticklers by presenting a variety of usages and leaving the reader to decide which is correct. Dictionaries fail to update meanings often enough. And due to space constraints in the print editions, many dictionary definitions are so concise as to be unhelpful. Ever run into a definition like this one for calumnious: "of, involving, or using calumny'?"
Perhaps, though, dictionaries just need to change with the times, to update themselves to be more relevant. Or, has Google improved upon this system so that much that dictionaries - either online or in print - are no longer helpful?