Last week, I ran a poll about the number of ebooks people purchased each month. The results suggest that most people don't buy ebooks, but get them from various free sources, such as Project Gutenberg, Biblomania and O'Reilly Open Books. Fifty-nine percent of respondents said they bought no books during the month.
However, the buyers more than made up for the free reading public. If we take the middle point of each of the ranges of books purchased (e.g. 1.5 books per month for those who said they buy one to three books up to 11 books for those who answered "10+"), the average number of books purchased during a month for all 147 respondents is 1.45. This suggests that, just as "free" seeded the Web 15 years ago and throughout the Web 1.0 and 2.0 epochs, free ebooks are creating the basis of a profitable marketplace for authors and publishers who deliver new value to readers.
The next question to ask, though, is what you would like to read on an ebook reader or, for that matter, in a document on your computer that could integrate your notes and highlights from other forms of the same book. This would allow you to go back and forth between devices with the same book, which I believe is a critical feature for the success of digital documents, because we already do it with business docs, printed and digital books, but without any integration of these different engagements with the information we're consuming (to some degree, collaborative editing of a document proves this idea is valuable--but it is the collective use of the information that makes new value available to people).
So, here's poll #2 in this series: You should pick one kind of document that, if it would make you buy an ebook reader to use for both reading books and this kind of document, you'd become (or already became) a buyer.