So you like my writing enough to re-use it? Awesome!
The following is a contract:
If you do not send the email you still have my permission as long as you reference and link back, but I do not promise that the license will be granted in perpetuity. In other words, I may change my mind. :-P
I will not grant the license if your site is merely a clone of mine. Create some of your own content or at least conglomerate other content as well.
Additionally, while I am honored that you are using my content in a book, the majority of the content must be your own. Otherwise let's talk royalties. ;-)