There are about 275,000 books published in the US every year (
Bowker - 2008). The 1st problem authors have to overcome is to get an audience. Lending ebooks is the best sort of word of mouth - the kind that gets you new readers. If the borrowers like one of your ebooks, they might actually buy others. The real problem with this program is that an evangelist who really likes your ebook can only lend it once. On the other hand it was a minor miracle that B&N was able to get publishers to agree to any lending.