In response to User talk:hapa#ISBN
Thanks for your interest in my wiki. Here's a tutorial on how to Hack mediawiki isbn for affiliates This tutorial was written to add your affiliate number into the Mediawiki ISBN feature.
It was an involved, trial and error process. If you decide to do this, be careful that you don't break your wiki (back up your files)
As for the bookmark sidebar see User talk:Dryguy
BTW, I've had more luck earning money with Adsense ads than Amazon ads