Okay, I tried it out. I watched the links and cookies as I went, and you are right - the affiliation ID disappears after the first page- hopefully it is stored in their "cookie jar" on their server (at least they are doing things the correct way, unlike many (most?) sites). Let's see if this works!

I also noticed that you can enter a "discount code" after you place the order and log in as a returning customer. Perhaps perlmonks could get a code to use there as well?

I used a discount from work in the code box and wound up getting an additional discount. (25% total) I don't know if it was related, but the fatbrain reciept that was e-mailed to me claimed $140 extra for shipping! That was fixed by the nice people at fatbrain. I had also filled out most of my order and came back a few days later, logged in, and my order was exactly as I had left it. Thank you vroom

I also noticed while poking around (tip of the hat to ybic) that the Buy Stuff page has an affiliation "From" for the book links and the "Quick Search" box, but not for the "More Info" and "Related Titles" hyperlink. I might humbly suggest that we give perlmonks credit for people clicking these links as well, if it tracks as the search box does.