Does the kickback for giving your ebook away justify giving it away for free? If not, and exposure is what you want then your lists are more valuable than the 1.00 or .10. The average user must see your messages 25 times on the internet before responding. If exposure for your business/wares is what you really want and you can't get it by giving your ebook away then maybe reconsider. If the nominal fee is what you want, then maybe this tactic is fine. Or maybe you could just beat your chest a little louder in your own e-book. That increases exposure also.
-Chris Dixon
http://www.profitpassion.com