I looked into turn.js and the licensing is beyond my understanding:

The turn.js project is released under the BSD license and it's available on GitHub. This license doesn't include features of the 4th release.

The part about 4th release seemingly links to a pdf but redirects to the same page.

Going to github I find the following:

https://github.com/blasten/turn.js/blob/master/license.txt

""" turn.js 3rd release

  www.turnjs.com

  Copyright (c) 2012, Emmanuel Garcia

  All rights reserved.

  Redistribution and use in source and binary forms,
  with or without modification, are permitted provided
  that the following conditions are met:

  - Redistributions of source code must retain the above copyright notice,
  this list of conditions and the following disclaimer.

  - Any redistribution, use, or modification is done solely for personal
  benefit and not for any commercial purpose or for monetary gain.

  THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ''AS IS'' AND
  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  SUCH DAMAGE.

"""

Not exactly BSD as far as I see (is there a non-commercial BSD license subtype?)

Furthermore I'm not the only one to wonder: https://github.com/blasten/turn.js/issues/491: Commercial licence turn.js

And in the comments on that issue: "I'm waiting for about 2 years now for an announced / promised update. "

Edit: added line breaks

Proprietary JavaScript libraries seems like a pretty common business model these days. What happened to the old GPL with selling exceptions model?

My point was I think he/she/they misuse the term "BSD license". As far as I know the "BSD License" is a pretty well defined thing, and not this thing. (I might be wrong, therefore the question in my first post; -I try to be careful.)

Furthermore it seems they don't reply to tickets or mails about selling an exception.

It's kind of like a candy store right outside school carrying a big "Teachers only!" sign : )

No comment on the license itself, but I did have to pay to use it.

Thanks for the update - I guess that means one can still get a commercial license, you just have to know where to ask.

As "GoldenCrow" states at the github issue from your link, it appears one can obtain a license at http://www.turnjs.com/get (Wherever this link comes from, anyway. It seems it isn't on the main page itself, which is weird.)

This whole licensing mess and misunderstanding is preventing me from using this library now, which is sad, because it seems it's actually pretty good at doing its job.

Based on how good the notes looked, I feel like this can be used to create infographics easier and nicer than Photoshop. I am going to give it a try.