michael_nielsen

Of course, many (most!) users glance briefly at the book and then flip away, never to return.

A more informative number: total time spent by readers is about 250,000 hours, or roughly 125 full time working years.

And here's a few of the other countries with readers: St. Barthelmy, Palau, Kiribati, Anguilla, Montserrat, Comoros, Mayote. This means a lot to me personally.

I suspect few of those countries would see the book with conventional closed-access publishing.

An interesting benefit / drawback is that dozens of translations have been begun, but many not completed. I make no attempt to keep track of them, but a few include Japanese, Chinese, Russian, German, Portugese, and Lithuanian(!)

I don't keep close track of the monetary income. I made about $9k from the initial Kickstarter, and $10-$20k more in donations since.

If I'd understood better what I was doing I could easily have doubled or tripled those numbers. But it wasn't about making money -- it was a hobby/curiosity project that was about developing my understanding of a subject I find fascinating. The money has been a nice bonus.

An unexpected personal benefit has been a steady flow of Paypal donations through my inbox, often accompanied by thankyou notes. You better believe I read and appreciate them.

Dozens of people have told me the book helped them change careers.

Would any of this have been possible closed access? Of course some of it would have. I might have made more money. But on nearly every other metric, I suspect being open access was a 100x or more multiplier on the impact.

A common problem in open science is that unconventional forms of publication don't "count" in the traditional ways, for tenure etc.

(I get occasional emails from people looking to cite the book, telling me some journal editor wants to know where "Determination Press" is located. I've so far resisted replying "Everywhere", and just demurely tell them "San Francisco".)

To sum up: open access makes material freely available to people who would otherwise never even hear about it. This amplifying effect is not small, it is enormous. And it applies in parts of the world woefully underserved by the existing publication system.

To finish: a couple of short, standalone essays within the book that you may enjoy. Written for a general audience. On whether there is a simple algorithm for intelligence: http://neuralnetworksanddeeplearning.com/sai.html 

On whether deep learning will soon lead to truly general artificial intelligence (scroll down a bit): http://neuralnetworksanddeeplearning.com/chap6.html#on_the_future_of_neural_networks …

Some additional calibration data: an editor at a major academic press tells me great sales figures for a similar technical textbook in a "hot" field are typically about 5,000-10,000 a year. So open access has a factor 200x or more here.