Likes

I think there should be a “like” button.

Then when it comes to searching there should be a sort category that sorts your search by the most “likes”. It’s different to sales and ratings sort and is a valid inclusion I think

Would be useful and helpful I think

Maybe but it could be open to abuse… For example, an author could create multiple user IDs to log on and up-vote their item.

Sales and rating – which I believe you can only rate something you have purchased, is more reliable.