I did a little digging. Unlike the other sites I've been checking (publisher and otherwise), every book at Rosetta Books appears to be available at Amazon as a kindle. But first, a little backstory. In 2001, Random House lost a lawsuit to Rosetta Books. Contracts for stuff like books sell the rights to publish, and until recently, there was no specific "electronic rights" clause (ditto in the music industry, etc. etc. and back in the day, this was a hang-up for stuff like video as well). For at least a decade now, the standard contract has included electronic rights unless specifically negotiated out. But if you go back a few decades, you're looking at a gold mine of books that people do still read, but never sold the electronic rights -- and which have a long life before going into public domain, post micky mouse law.
Rosetta Books makes a living collecting these rights and then letting other online retailers sell the actual e-books -- they really are an e-publisher. Sometime around 2004 or 2005, Amazon started listing e-books (not kindle format, obviously!) from a variety of publishers including Rosetta, and Rosetta Books partner listing off to the left still includes a lot of these old links, which are now dead. Recall what happened after the breakup of Toys R Us and Amazon.
So what happened? I can only speculate. Which is what I will now do. I think that Amazon made some sort of deal with Rosetta to get that nice product placement link to sell its e-books, and Rosetta got some kind of cut and was happy and best of all, Amazon got to identify every e-book of Rosetta's. Which is why every single book I check over at Rosetta is also available as a kindle, at a slightly lower price than what the other, still-current retail partners of Rosetta is currently selling it out.
I figure Rosetta is still getting a cut of all those e-books (after all, it looks like they've got all the rights). So they aren't done for. But pity the partners.
A lot of the commentary on the kindle has asked whether it's the new iPod. I think that is in fact a really good question, but people are getting all laser-focused in on the look of the reader, and not paying adequate attention to the pricing structures and DRM decisions. .PRC/mobi is a native format on the kindle -- but only in its non-DRM version. And I don't think the kindle format is available on any other reader. Sound kinda like .mp3 and AAC? Like Apple, Amazon is doing a little bit to hoover up sales on other sites, but doing a lot to encourage people to buy on their site -- and making it non-easy to then switch to another reader.
There's been a good deal of discussion about the cost of content on the kindle, which people are comparing (unfavorably) to itunes content. Which is dippy, because it's clearly been matched (9.99/CD = 9.99/book). But a better comparison is to other e-books (see previous posts). So you save $100 if you buy the Sony. But if every single fucking thing you buy costs you $1-$15 more to buy for the PRS-505 than it would for the kindle, it's only going to take a serious reader a year to justify the extra $100. Maybe less.