If I buy a book from Amazon.com, and I get there by clicking on the "Buy it from Amazon" button on the PBS site,  does PBS benefit in any way, as opposed to my simply going to Amazon.com from the bookmark on my computer?

If so, I would try to remember to always get there from here; if not, I won't bother.

Anybody know?

See highlighted portion below...

What is the Buy it New feature?

Yes, PBS gets a small percentage of everything you put in your cart (except items from 3rd party sellers). So if you go to Amazon from a button here and buy electronics, groceries, etc, PBS makes a few cents.

you can add the book to a behind-the-scenes Amazon cart;

What, exactly, is a "behind-the-scenes cart?"  When I click on the Amazon button from here, I am routed to my own account on Amazon, just as if I had clicked my bookmark.   This is good, since I pay a flat yearly fee to Amazon for shipping (a great deal, seeing how much I buy from them, books and otherwise), and I would want that to work even if I get there from here, which it apparently does.    Should I presume the "behind-the-scenes" bit  simply means that I get there by a more circuitous route?

Sorry if this is a silly question, but I want to be sure before I do it.   I have a couple of books on my WL that I know I'll never get in this lifetime, so I'm resigned to buying them.   If I can benefit PBS in the process, so much better. 

I have Prime, too.  By going through PBS to Amazon they know how you got there to your account and nothing changes for you.  But Amazon will give PBS a small amount of whatever you spend while going there on PBS' link.  IT's sort of like a finder's fee or paying for advertising without actually advertising except for the button you hit.  I use it a lot when checking out books not just buyimg them.  And it's not just for buying books that they get the percentage.

a small amount of whatever you spend

It's not on "whatever you spend" - it's a percentage of what you spend on certain items.  Kindle books, for example, don't get PBS a penny - though if you buy a Kindle e-reader through a PBS link the site will get a percentage of what you buy.

Thanks, everyone, for your input.  My two credit cards also give a very small percentage of what I spend to causes I believe in.  It's great, because everyone comes out ahead.

I will try to remember to go to Amazon through PBS from now on.  

Thanks for the correction on the Kindle exception - I don't have one and don't want one so I wasn't aware of it.  But I do believe that most every other purchase will generate $$ for PBS.

Ruth