I'll grant you that K-12 teachers don't always have much, if any, influence over the books that they buy, but college professors? In my experience they have COMPLETE control over what they teach, particularly senior faculty, as they can pretty much tell the bookstore to stock whatever they want. What they lack is a set of visible, viable alternatives to what they and their colleagues have been using, which is what these initiatives are trying to accomplish.

Your example of college algebra is precisely the reason that this sort of thing WILL work - not overnight, but eventually. At some point, professors are going to realize that that, collectively, they have more knowledge than what's available from a single textbook, and all it takes is an agreement to share that information freely in order to have something bigger and better than what we have now. We don't need to continue to rent an inferior product at an insulting price when we already own that knowledge.

This is, of course, a fallacy, albeit one that is very commonly accepted by professors and encouraged by publishers. Of course, the only way to break out of this cycle is to get people to see through the false assumptions and take a leap of faith, and hope others follow suit.

One of the things we've done with Connexions is to introduce a feature we call lenses, which is a sort of post-publication review process that allows individuals or organizations to endorse content that's already freely available. In short, it gives you the confidence that someone has signed off on the quality just as an editor would with a traditional textbook (which, it should be pointed out, is not guaranteed to be accurate, effective, or even worth its weight in salt). Will this catch on? Time will tell, but I think we're definitely moving towards a model where we get more authors involved in the process who are interested more in gaining recognition and contributing to their fields than in a measly royalty check. A globally-accessed open education site like Connexions or some of the others mentioned here offers many authors - especially young authors or those and those shut out of the traditional model - an audience of potentially millions of readers who can access content through Google rather than a few hundred who were forced to shell out $100 for a book they really didn't want to buy in the first place.

Let me know if you're interested in hearing more about Connexions. I haven't had time to review all of the contents as this has turned into a really deep discussion, but I can tell you that it addresses several of the concerns here: searchable by Google, free access for students, print-on-demand options as well as online access, and completely open (CC-by) licensing of content. For those arguing against giving away content because of lack of ROI, I recently posted a blog post describing several ways that authors can actually benefit from using a site like Connexions (or, to be fair, any widely-viewed open education site). My role is as the primary author and community support person, as well as a "salesman" of sorts, so if you have any questions or want help getting started with authoring, feel free to give me a shout at cnx at cnx.org and I'll be more than happy to assist.

Regardless of which site or service you end up going with (all have their own pros/cons and licensing philosophies, so it's certainly not one-size-fits-all), I definitely encourage you to think about open licensing, and would be happy to chat about that even if you have no interest in Connexions itself.