Good that you learned a lot - didn't know people still used KnockoutJS, but looks like you did well on this one.
Btw, another thing I noticed is that clicking the expand comments button a second time does another request to fetch the comments - might want to check client side if it's already fetched first, and also make sure that the requests are cacheable. Looks like there's some `no-cache` headers set. (btw2, I was in fact expecting it to toggle the comments, ie. close them, but that's another thing)
Also, it seems like you manage to rewrite the normal amazon links in comment bodies to add your affiliate code, but the smile.amazon.com-links remain unchanged. Not sure if this is intended or not, but might be worth checking out.
Thanks for the tip! Saw that post when it was on HN originally, also pretty cool :)