I read all my books on my iPhone and my idiosyncracy is to have different books open in various ebook readers at the same time. This is a drastic change from my lifetime habit of reading one book at a time. I never knew I’d enjoy reading this way because the physical limitations of carrying paper around never encouraged me to consider it.

At the moment, I’m reading “Joe Cronin” by Mark Armour and “Crossing the Chasm” by Geoffrey A. Moore on Google Books; “Washington” by Ron Chernow on the Nook reader (which I see now has lost my place and is forcing me to figure out where the hell I was, which is not a good thing); “Brooklyn Dodgers: The Last Great Pennant Drive” by John Nordell in Kobo; and “The Autobiography of Mark Twain” in Kindle. I have the iBooks reader on the phone but I never shop there because I never saw any particular advantage to the reader and they have distinctly fewer titles to choose from than everybody else.

Now, did you care about the details of that? I’ll bet most of you didn’t, except to the extent that you expect me to make a conceptual point that makes it worth knowing that highly personal detail (which, of course, I will.) My hunch is that most of you would have been just as happy to move on from the first short paragraph above and not require the detail from the second one which, frankly, is not really necessary to make the point. But a few of you are very interested (but please don’t tell me your details; I’m part of the majority.)

Where I buy the books is very haphazard. My order of preference for reading (at the moment; it changes and I use them all) is Kobo, Kindle, Google, Nook. Kobo, Kindle, and Nook have built-in dictionaries; press (not tap) on the word and you get a definition and an opportunity to make a note or link out to Google or Wikipedia. The problem for me is that, on the iPhone, I can’t always make this feature work. My personal experience is that the functionality is most reliable on Kobo, and considerably less so on Kindle and B&N, but whether that experience is representative of what others will find with different iPhones, different fingers, and different titles, I don’t know.

Google doesn’t yet offer this capability or even simple dog-earing of pages (which the others all have), but I’ll bet they will have it before long.

None of the platforms delivers perfect performance in my anecdotal and ad hoc experience (and yours might differ). I have had Kobo “lock up” so I had to reboot my phone to get it working again. I just got a rendering of “Mark Twain” from Nook that was a formating disaster on my iPhone. (I told some people at B&N about it; perhaps it is fixed by now. When I asked the publisher, UC Press, I was told the file worked on the Nook device, but I know it didn’t work in Nook on my iPhone. It reads fine on the iPhone in Kindle.) Kindle is frustrating for me because I strongly favor reading ragged right and, as far as I can tell, Kindle always delivers justified pages with no way to turn justification off. I find Google and Kobo deliver the navigation that feels most intuitive to me and the most control of the reading experience. Nook doesn’t seem to have a way for me to lock in the vertical screen, so you can’t read in bed and have the type conform to your head if you lie on your side.

If I think of a book I want when I’m reading another one, I’m most likely to just buy it in the reader I’m in just because I have it open. Thanks to the combination of agency and 24/7 price monitoring, there is unlikely to be any financial advantage to shopping around. If I know exactly which book I want, there’s also no particular distinction among the four for ease of use or speed of transaction.

There is one dynamic that clearly favors Kindle. I own a Kindle device, one I bought in the first week or two they became available. I read many books on it over the first year or so. I gave it to my wife when Kindle made its vast selection available on the iPhone. Martha reads a lot more books than I do; we read relatively few in common. But when I decided I wanted to read Stieg Larsson, she’d already bought it for Kindle so I read it in the Kindle reader (it’s all one account.) And when I bought the new Ken Follett from Nook, she accessed it in New York while I was reading it in Frankfurt by using the iPad that we share (but which neither of us favor for reading books because it is too heavy.)

All of which leads to the conceptual question which I promised above was coming: what’s a retailer to do to create loyalty and lock-in among customers? And in addressing that question we must also keep this in mind: small groups matter.

We will look back and say that it was a relatively small group of early adopters to Kindle that were the key catalysts to profound and accelerating change in book publishing (change which is still in its infancy.) Amazon was in a unique position to deliver a real value proposition to the people who could benefit most from a lightweight reading-only device. And they captured and, for a while, locked in a relatively small group of very heavy readers, because the more books you read the greater is the relative benefit of Kindle, functionally and financially.

There may well come a day when the (relatively) closed file format of the Kindle becomes a handicap to sales but it is hard to see why it would be now, particularly if Amazon delivers on their recent announcement of a browser-based Kindle reader coming shortly. (I should add that I’ve read reports that Google books work fine in a Kindle device through the Kindle web browser. Since my own Kindle is an original, without wifi and with a very slow connection, I’m not in a position to confirm that.) But, for now, Amazon has many millions of happy device owners for whom buying a book any other way is likely to be more trouble than it could possibly be worth.

So, how else does the retailer lock the customers in? Google has tried to sell the value of being the manager of your “locker” where all your books will be available to you all the time, on any device, etc. The idea seems to borrow from the iTunes concept, but this is another example which reminds us that “books ain’t music.” It matters to have all your music in one place. I will never have any reason to need “Washington” and “Joe Cronin” in the same reader but I could listen to a song from 1958 and a song from 1992 consecutively anytime.

So the keys to iTunes were a) enabling you to rip your CDs easily, for which the database of linked metadata was actually the critical feature and b) enabling you to buy any other music you wanted as downloads into the same hosting system. I may be a bit extreme in the disorganization of my reading habits, but I think very few people would require anything like the aggregating capabilities of iTunes for their reading material.

So, how else? Copia (our client for most of the past year, which will be on my iPhone as soon as their iPhone app is available) has a proposition that addresses this, which is to deliver a social network application in conjunction with the reader. If I were on Copia and had all the books I am talking about in their application, you would have been able to see the detail I presented in the second paragraph without my having to say so.

And that takes us to the second point: that small groups matter. Because, clearly, there are people who do care about what others are reading and who want to annotate what they read for others to see. And if I did care about sharing my reading experiences, I would want all my books in Copia. That’s lock-in. And, who knows, maybe I’ll find that sharing information with other baseball history nuts will be worthwhile. (Although I wonder if I’m the only person who finds the subtle underlining in Amazon that will tell you when moused over that “87 people highlighted this passage” both pointless and distracting.)

Locking in a small group is likely to be what Kobo has in mind with the new social reading capabilities they just introduced. They are available right now only in the iPad version of the app, but they “track” your reading for you, give you badges for finishing a book, and easily enable you to broadcast to the world where you are in your latest doorstop. The people who find this compelling, and there are some, will now have a reason to use Kobo and nothing but Kobo, just like the people who own Kindles have a reason to use nothing but Amazon and Copia hopes to gather socially-minded readers who would get less value anywhere else.

I expect that the core capabilities will even out over time. Google will add outbound links to dictionaries and reference sources. All of the platforms will improve the responsiveness of their iPhone app to my stubby fingers. If Kobo’s social statistics prove a draw to consumers, the others will add something similar.

One thing I have found that is really cool about reading on the iPhone is the ability to do a screen grab as a photo, which then allows me to send the photo as an email. There’s a fabulous graph in Robert Reich’s new book “Aftershock” which makes plain as day the fact that the one thing that tanks the American economy is the top 1% of the people getting too much of the national income. I loved being able to grab that chart as a photo and send it around to friends. I think one iPhone screen of content has to be small enough to be legitimate “fair use”. (That’s my story, and I’m sticking with it.)

But what matters most to me is the merchandising and shopping experience, which Kobo has the best so far but not by enough to matter a lot of the time. (And, as I pointed out above, if you know which particular book you want before you shop, they’re all the same and really hard to improve on.) There are many ways the shopping experience can be improved by all of them, but I’ll save my thoughts on that for another post.

So most of the horses are out of the starting gate and Amazon has clearly taken the early lead. But anybody who thinks the race for retailing ebooks is over should contemplate this: we don’t even know yet what distinguishing feature set will win, let alone who’s going to have it in the long run.

I realize this analysis is incomplete. It doesn’t account for stand-alone readers like Liza Daly’s IBIS Reader nor does it account for independent ebook retailers such as the pioneering Diesel Ebooks. It doesn’t cover Sony, which might still have a larger chunk of the market than Kobo (although, if they do, I predict it won’t be for long). Back in the days before Kindle, when I read my ebooks in Palm format on Palm and other PDAs, I shopped at Diesel. I don’t write off anybody’s chances at such an early point in the development of the ereading infrastructure, but I think my iPhone and this post capture the sources that offer the biggest selection of content that would interest me. And I’m reasonably certain that I’m reporting here on the players that serve up the overwhelming majority of the ebooks read in the US, well over 90% and probably closer to 95%.