CI Book

[eluser]skunkbad[/eluser]
[quote author="ckdarby" date="1349366821"]@skunkbad Last time I looked at the license I didn't notice anything this harsh but it has been a while but I think @Aken is correct[/quote]

You should carefully read over this:
http://ellislab.com/forums/viewthread/202562/

I participated in that thread, along with administrator Derek Jones and many other forum members, and it seemed clear that you DO have to make the source code available to your website visitors, and that the method you choose to do so is up to you. You can't make the source code available without revealing the technology used to build the website, which would make a hacker smile from ear to ear. No matter how great a developer you are, we all make mistakes, and I already have one customer that has said we won't upgrade to 3.0. It's just too risky. Just as suggested in the thread, you are advised to seek proper legal counsel in regards to your fulfillment of obligation when using the new CIv3. It was stated that there was an option to pay EllisLab for a special license.

You're likely to hear a lot about this when CI3.0 is officially launched.

Actually, if you wanted to add something really cool to your book, you might consider hiring a couple of attorneys and having them give you advice or recommendations on how best to comply with the terms of the license.