In a recent opinion piece for Edsurge, entitled OER: Free Like a Beer, or Free Like a Puppy? , David Ciulla did his best to obscure the difference between Free and OER. He also did a very fine job of positioning his company, a non-profit, as a best bet for being the provider of choice to the K12 sector in the market of ELA products. He says "it’s too early to draw definitive conclusions about how the content market will shake out, and what the implications will be for various business models and growth strategies. He also says Readworks hopes "that there will be a vibrant and lucrative private-sector market for companies that are creating superb ELA products that make teachers much more effective and make students much better readers."
Yeah, I know, that doesn't sound like the language of an executive director of a non-profit providing free content to free public schools. I'm suspicious; I think there's a hook coming. I'm not sure what that hook will look like; it might have something to do with the coming Data Evaluation on the Digital Readworks. Maybe, I'm just being too suspicious.
Here's what I know for sure: Ciulla isn't even close to being interested in explaining the difference between OER and Free. He used the phrase 'free and oer content' 5 times in his piece without ever making a distinction between free and OER. That's after using OER in the title in combination with 'free' and in the sentence where he points out that the claim "free curricula and OER content were hardly free once the related costs and risks were factored in" is well reasoned. After reading Ciulla's opinion, someone who wasn't sure about the difference between free and OER, which would include about 99% of the people on planet earth, could be excused for thinking that that free and OER are pretty much the same.
So, what's the difference and why does it matter? You'd think a company, whether private or non-profit, that was dedicated to providing research-based materials to teachers to boost students’ reading comprehension would want to help teachers understand the difference between OER and Free content. Why would anyone involved in teacher support in 2016 Not want to help teachers understand the difference in OER and Free.
Here's the Hewlett Foundation definition of OER - "OER are teaching, learning, and research resources that reside in the public domain or have been released under an intellectual property license that permits their free use and re-purposing by others. Open educational resources include full courses, course materials, modules, textbooks, streaming videos, tests, software, and any other tools, materials, or techniques used to support access to knowledge." 
The big difference between OER and Free is that Free isn't necessarily OER. Free content doesn't necessarily allow teachers to revise, edit, remix, change, make the content more relevant to the student. OER content allows teachers, depending on the particular license, to do whatever is necessary to make the content better for students. OER empowers teachers to do all kinds of things with content for their students; free just reduces the cost.