Supporting the Free Software Foundation's day against DRM

Why is is okay for me to give or loan a book to a friend but not okay to do the same thing, with the same content, when it is in the form of an eBook?

The O'Reilly Media, the publisher of my ebook Virtualization: A Manager's Guide, is taking part in the Free Software Foundation's day against DRM. I thought you might like to know about what they're doing.

Here's what they have to say about it:

In Celebration of *Day Against DRM* Save 50% on ALL Ebooks & Videos

Having the ability to download files at your convenience, store them on all your devices, or share them with a friend or colleague as you would a print book, is liberating, and is how it should be. If you haven't tried a DRM-free ebook of video, we encourage you to do so now. And if you're already a fan, take advantage of our sale and add to your library.

For one day only, you can save 50% on all O'Reilly, No Starch, and Rocky Nook ebooks and videos. Use code: DRMFREE

Ebooks from oreilly.com are DRM-free. You get free lifetime access, multiple file formats, free updates. Deal expires May 4, 2012 at 11:59pm PT and cannot be combined with other offers.

I've always thought it odd that it was fine for me to loan or give a book to a friend, but doing the same thing, with the same content in the form of an eBook was not allowed. I'm happy to see that FSF is saying something about this topic.