Writing book reviews (on Amazon)

Sometimes I want to comment on a book, which I can do in different ways:

• I can write a public review on Amazon
  
• I can create a personal book list on Amazon and add very short comments
• I can make an Amazon-reading list on LinkedIn and write more
• I can write elsewhere on it, like on a blog

If I make a book list on Amazon, I have to enter the code in order to get the book on the list (which I have to look up, not very thrilling). This is probably one of the worst parts of Amazon's customer experience:

What would help me:

• use the normal amazon book page with a function "add to your lists"
• use my shopping list of books, with an feature "add comment" to the books I have read/bought
• import my lists from Amazon to LinkedIn or vice versa
• or ...
  

Does it matter much if people read reviews on blogs, LinkedIn or the amazon pages? Or do more, more usable, desirable book reviews on the web mean more "share of attention" and therefore more share of wallet for Amazon?

What do you think?