Ratings 
Ratings allow the quality of a document to be evaluated by its readership. You can evaluate a document on a scale. If you want to know how other people have rated a document, you can display the average of all ratings.
Prerequisites
This function is only available if the rating service is active for the repository. This setting is made by an administrator. For more information, see Collaboration Services.
Features
Rating a document involves evaluating it according to a prescribed scale. The scale depends on the configuration used by your enterprise.
Each user can rate a document. You can repeat the evaluation if your opinion has changed. When calculating the average opinion, the system always takes your most recent evaluation into account.
Note
You cannot rate documents or folders that you created yourself.
If other people have already evaluated the document, the average evaluation is shown. The total number of readers that have evaluated the document is also displayed. This allows you to decide whether the average evaluation is significant.
Ratings for folders
The rating function is also available for folders. You can use this function to evaluate the compilation and contents of documents contained in a folder.
Activities
You evaluate documents and folders in the appropriate Details dialog box.
If you are searching for documents, you can sort the results list by rating so that the documents that have been given the highest rating values appear at the top of the list.