The power of the gatekeeper

I was reading the blog of Seth Godin, http://sethgodin.typepad.com/seths_blog/2010/08/just-launched-linchpin-on-the-vook-on-the-ipad.html and I realized that we have ebded up in a world of two ebook marketplaces: Amazon and Apple. There are many others to be sure, just as there are many other sites on the Internet, but they are not built into the reader, so most people feel it is too much work to get to them. Even if it is only a matter of a couple of extra clicks. Such is the power of laziness.
Microsoft and B&N have a fighting chance of creating a third, which I hope they are working on. Google could do it in the Motorola tablet I am sure will be coming, but they might get hit with lawsuits for having Google Books, so if I were they I would refrain.
Which means we are stuck with two major platforms and the rest. Unless you are confident you are going to sell a lot there, you will probably focus your efforts on the two major platforms, if you are a publisher or author/publisher. That is going to make it extremely hard to stand out. And there is another thing: it is going to be very hard to have a discussion with your customers. Note discussion, not dialog. Publishing a book is not like a blog or newspaper, where the audience has a say in where you are going. It is about your ideas, not theirs. If they do not want to hear, fine.
In non-fiction, it becomes even more important. The facts are given. The rules of the road, to take my own case, are what they are. Explaining given things, or teaching a new method of learning and using them, are what non-fiction is about. You may have an opinion on the method of teaching or using the laws of nature or the rules of the road, but in particular when it comes to laws of nature they will not change. So the discussion is not about the subject matter.
Which is not to say you can not have it. But not in the iTunes store or Amazon, not in a useful way.