How many Kindles are really in use? As far as I can tell, Amazon hasn't released any Kindle device sales figures, other than a quote referring to "millions" of users. Several analysts have jumped on the use of the plural as evidence that at least two million Kindles have been sold. But I think the BISG survey doesn't support that. Here's my math:

--About 2% of book buyers have ebooks and/or ebook devices.

--About a third of them have Kindles (that's 0.67% of active book buyers).

--If 0.67% of book buyers in the US is two million people, then there are 300 million active book buyers in the US. That is the entire US population, including infants and people who don't like books. I don't know what the base of active book buyers is in the US, but my guess is it's not over 200 million, meaning the installed base of Kindles would be about 1.3 million.

It's tricky to play with survey results when the percentages are this small -- the margins of error become very significant. But for now I think the BISG survey raises some questions, and I'm not willing to accept the two million figure for the Kindle installed base without some more rigorous evidence to support it.

Other tidbits

BISG is not going to release all of the information from the survey (that goes only to the companies that paid for it). So I took as many notes as I could during the presentation. Here's what I captured:

Ebooks are somewhat cheaper than hardcovers
On average, an ebook costs $6.25 less than a hardcover book. This is a huge issue to the book publishing industry, which worries that ebook sales will cannibalize hardcover book sales. My comment: Of course they do, get over it. The thing publishers should be looking at is the much higher margins they make per ebook sold. I don't know of many industries that resist moving to a higher-margin product, but publishing appears to be the grand exception. Of course, the thing worrying publishers is the decline of independent bookstores, and they're afraid ebooks will accelerate that. But the decline of the bookstore has almost nothing to do with ebooks -- it's being driven by online sales of paper books and predation by retail chains.

Demographics
-Ebook buyers are 51% men (compared to 58% women for paper books).
-Ebook buyers are higher income than paper book buyers. Not a lot, but significantly higher income. No surprise there -- most poor people can't afford several hundred dollars for an ebook reader. Betcha they don't buy a lot of hardcover books either.

Cannibalization
Among ebook buyers, 11% no longer buy any paper books. 8% buy mostly ebooks, and about 30% prefer to buy ebooks. So about half of ebook users prefer ebooks to paper books. That's actually a lower percentage than I expected for something that is supposed to take over the world. But remember, half of ebook users are reading on PCs. What I really want to know is the percentage of Kindle users who prefer ebooks; that'll tell us how satisfied Kindle users are.

Preferred device used to read ebooks
-PC: 47%
-Kindle: 32% (and rising in later waves of the survey)
-iPhone: 11%
-iPod Touch: 10% Hmmmm! iPod Touch really is a PDA.
-Other smartphones (including Blackberry) 9%
-Netbooks 9%
-Sony Reader 8%
-Barnes & Noble Nook 8% (the BISG folks noted that Nook was just starting to sell at this point; they believe some users confused Barnes & Noble ebooks with the Nook device)

Genres of ebooks
-General fiction, 31%
-Mystery 28%
-How To 25% (but #1 over Christmas)
-Science Fiction
-Biography
-Business

Some folks are going crazy over ebooks... that's why I decided to start looking into these a bit more (indirect request from a client as well).

As Michael points out in this excerpt above... perhaps the whole thing is being overstated... exaggerated... blown out of proportion.

But what for?

(With this post I started a new category ... "Truth In Numbers")