Sourcing Resalable/ Rights Free Information Products

Hey People,

Im sure you have seen the thousands of sellers on ebay that sell DVD guides/how to's on pretty much every subject under the sun. I know that back in the day these sellers were emailing these guides, but its now banned by ebay so they are having to be posted out.

I was just checking some of them out, and got wondering, where are they sourcing these DVD's/guides that are allowing them resale rights?

Its impossible that they are making there own information products, as many of the sellers have hundereds of listings selling so many varieties of guide/DVD, such as this seller, marie17681 who has got 787 DVD information product listings up right now!

Most of these auctions state stuff like :

Contents of this item is distributed freely and globally under the terms of the GNU Public License, the GNU Lesser General Public License (LGPL), or is Freeware, with free/open distribution license, or is distributed with full permissions of the rights owner.
This item does not infringe any copyright, trade mark, or other rights or any of eBay's listing policies.
Seller has full and legal authority to sell this product.
It is not an unauthorized copy
Proof is available on request

Are these people simply buying of each other, ripping the information and making it look like their own, then selling it as their own ?

I have an ebay account and a bit of time on my hands and a lot of bills to pay. I was hoping to make a little cash from a selling some of these information products, but im having a hard time sourcing any of the sellers. Some of these sellers have literally hunderds of differant products........

Thankyou in advance for any comments or insights into this business model and the sourcing of the products.