Simple rebrandable ebooks have proven to be very effective at growing an email opt-in list. By allowing others to change affiliate links, or blocks of text within an ebook on a hot topic, they are encouraged to distribute your list-building links far and wide.
Webmasters and ezine publishers scramble daily to find fresh content on hot topics for their websites and ezines. They want to give, or sell, this information to their insatiable audiences.
Knowledge grows exponentially, and there is a huge demand for the latest of that knowledge to be summarized into digestible pieces. Ebooks are a great way to distribute that information while creating a list-building virus.