The front-page warning says "However, we want to be clear that this edition is only free to read online, and this posting does not transfer any right to download all or any portion of The Feynman Lectures on Physics for any purpose. "
I wonder how they expect people to read it in their browsers without the text of the document being transferred down to the computer on which the browser is running...?
Not to mention the implied requirement that an always online connection is required to read these 'free' editions, rather than being able to read from a local copy offline.
Yes, yes, we all know that in the modern day everyone has an internet connection to the cloud all the time, so this is an old-fashioned sentiment. Or wait - maybe it isn't so old-fashioned. It's still quite common that in situations where there is enough idle time to read something like this (on a plane, train, boat or automobile; in a remote vacation cabin in the woods etc) there isn't an internet connection available. Not to mention the times I deliberately set my tablet to airplane mode just so I can read a book or magazine without being distracted by notifications or tempted to look at something else online.
I'd also think that these lectures would be quite useful to those in poorer countries that don't have the funds to have an always on internet connection available personally at home, but might have access to a library or other venue where a public internet connection is available.
I appreciate their graciousness in making these lectures available gratis, but that front page warning does seem to be a bit counter to the spirit that probably drove this effort.
Personally, after glancing through some of the chapters in the first volume, I think that maybe releasing the material under whatever Creative Commons license allows them to retain the rights they want but enables people to share and contribute updates might be preferable in the long run. I'm thinking not so much of the text itself, but many of the figures seem rather outdated (eg. a poor photograph of some old ball-and-stick atomic models) and could benefit from some cosmetic updating to make them more suitable for modern eyes.