Remember that Radiohead experiment back in 2007, the one where they allowed free downloads of their latest album and asked listeners to pay what they felt was fair? Some say it was successful and others beg to disagree. Assuming Amazon ever gets back to an in-stock inventory situation with the Kindle I think they should try a similar experiment with a big-name author's next book.
Why? First of all, it would be interesting to know how much value readers place on content, particularly e-content. Secondly, although some customers won't pay a penny for it, others will and it's that data that would be so fascinating to study.
Then there's the PR opportunity for Amazon, publisher and author. Imagine how much free publicity this would generate. It would probably open that author up to new customers who've never read his/her previous work. But for Amazon it's an opportunity to generate a lot of buzz about a product they do almost zero advertising for; sure, they're out of stock, but again, I'm talking about the value of this when (if?) they ever get inventory again. As I've also said before, I'm amazed at the number of people (including regular Amazon customers!) who've never even heard of the Kindle.
Btw, just like the Radiohead deal, this would be a limited-time offer. Unlike the Radiohead deal though, I could also see an opportunity for Amazon (and the publisher/author) to sell sponsorship of the event. An ad (or series of ads) would appear in (or periodically throughout) the free Kindle edition of the book. This would help offset the lost revenue from downloaders who turn out to be freeloaders. Then again, is that really "lost" revenue? Those people probably wouldn't have bought the paid edition anyway.
Only a very forward thinking publisher and author would participate in something like this. It's not without risk, of course, but it's also an experiment in a very limited space; the number of Kindles out there is tiny compared to the number of book-buyers who don't own a Kindle. So even if it's wildly popular but nobody pays a penny for the content the other 99.999% of the book-buying public won't have been affected.
Speaking of that other 99.999%, Amazon, publisher and author could use this as a way to promote the book to that majority as well. Think word-of-mouth and add in an affiliate discount code Kindle downloaders can pass along to their friends, creating even more buzz and giving everyone an additional incentive to buy the book.
One final thought: If a publisher really wants to do this they wouldn't even have to work with Amazon to make it happen. They could simply offer the unprotected mobi file on their own site for a free, limited-time download. Think about that for a moment... That publisher would be able to establish a direct relationship with all those Kindle owners, capturing e-mail addresses and the opportunity to market directly to them in the future. Take that a step further and if the publisher makes it clear to the customer, they could conceivably sell that list to other publishers to market to them as well.
See all the interesting directions this can go in?...