Anytime I review a book here on my blog I also try to (remember to) cut-and-paste that same review on the book's page on Amazon. One of the biggest frustrations I run into when doing this is Amazon's policy against embedding HTML in customer reviews.
I figure there are two reasons why they don't want you to embed HTML in your review: loss of traffic and dead links. Neither one of these are bad enough to warrant Amazon's policy against them.
The primary reason I'd like to embed HTML in my reviews is to offer links to related sites/pages. Yes, those links will cause customers to visit pages outside the world of Amazon. Big deal. Is Amazon really that concerned that they'll lose a customer because of an outbound link?! If so, I think they're really underestimating the power of their own brand.
The dead link issue is equally lame. Dead links exist on just about every site. Would I think less of Amazon because I found a few there in customer reviews? No. Plus, Amazon tends to be pretty innovative with services and features -- couldn't they harness some of that energy to write a tool that periodically crawls their own site, stripping out dead links in customer reviews?
Embedded links in reviews will only serve as another feature for Amazon's customers. These links will help customers with their purchase decision by providing additional information, much more than can possibly be squeezed into the actual review. I think Amazon should consider these customer benefits and rethink this policy.