I think it all depends on what the purpose is.
Sometimes giving something away for free can still have a 'value' for the giver, without requiring anything from the recipient.
For instance - free 'viral' e-books. They don't require any further action on the part of the recipient, but if they are happy with their gift, they may be inclined to click on one of your links. If they like the book enough to offer it for free to their list, even better.
Free gifts as an enticement to subscribe to a newsletter. OK, sure, you are asking them to subscribe, but if they don't enjoy your newsletter, they just unsubscribe.
There are more involved give-aways that are still essentially free - take my 'Partner' Program.
Applicants get to have a page promoting THEIR business, hosted on the site (and a whole lot more) for free. All that is asked is that they include a link back from their own site, or if they don't have a site, that they use the page as an entry page in their promotions.
All 'partners' get increased traffic viewing their business proposals, at no cost.
Of course I benefit from increased traffic to my site, but this doesn't 'cost' partners anything, except some time.
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