First of all, I am sorry if I offend anyone.
But when I see a free ebook offer that wants my name, mailing address, email address, and also states that they will be passed along to other places that may have product I may be interested in, I consider it as requiring more information than I am willing to give and pass on it.
If a publisher is offering a free ebook on any site, it should be made available without having to fill out a form with lots of info about the requester.
Those are just my feelings on this and I am not inferring any ill against the publisher or LinuxQuestions.org.

8-bit, thanks for the feedback. We partner with a third party to provide the gratis ebooks and the partners that participate in the program often require some amount of information in exchange for getting the ebook at no cost. We understand that for many people, the information they require may be too much. In those cases you're of course free to not participate.

--jeremy