What on earth is IBM Watson?

If you're following tech news, you'll see mentions of IBM Watson nearly everywhere in the past few weeks. Is it HAL 9000, a Turing test waiting to be passed? Or is it a collection of standard-ish machine learning tools paired with professional services implementations and a top-class sales/marketing org? IBM is consciously choosing to brand this varied work as Watson. It might confound tech pros who know that Jeopardy and chatbots are very different domains.