Amazon (US) hat auf den Produktseiten Wikis eingeführt! (kann schon länger her sein, ist mir eben aufgefallen)
Wiki provides a way for you to share your knowledge about a topic. Wikis are written and edited by groups of people. When you contribute to a Wiki you join a community of other people knowledgeable in the topic. Unlike reviews where each person’s opinion appears separately, a Wiki is a single file that is edited by many people.
You can create Wikis about a many different things on Amazon. For example, you might create a Wiki to describe a particular opera recording. Within that Wiki you could create links to Wiki entries defining words such as “soprano” and “coloratura”.
You can view how a particular Wiki entry has changed over time, to see who has contributed what and when, and you can subscribe to be notified by email of any future updates to Wikis you are interested in.
A list of Wikis you have contributed to appears on your Your Amazon Home and Profile pages.