Alpha is live now. I've written about it for InfoToday (link), and though my piece there spins a bit on the issue of epistemology, at the end of the day Alpha is a dern good reference and computational tool. That's what it's meant for, after all. And its quality will improve (see link to help it grow/improve).
The 'bigger' questions about knowingness and truthiness, etc. are (though important in the grand scheme!) unfairly localized on this engine. It doesn't claim to get its users to Truth, you know. I guess it's understandable that we web searchers drift to such questions when faced with such a fantastic machine.
Reminds me of a line V. Rev. Dr. Hegwood once used about ninjas... "they must exist because they're not online..."
So, Alpha came a bit too late to make it into the book (I did manage to pop off a mention in a late revision, but that was still before Alpha was live), but it does help my main case. Wolfram Alpha is one of the early popular semantic search tools.
They'll start coming out quicker now.