In BibSonomy, you can comment and rate publications and bookmarks very easily. This way, you are able to discuss publications with other users, write reviews or give your opinion on a publication in form of "stars".
In BibSonomy every user can discuss ressources (bookmarks and publications). Further information on this topic can be found here.
If you desire to rate an existing entry (bookmark or publication), follow these instructions.
Reviews written by other users for a publication/bookmark can be commented any number of times. To comment a review, click on the black arrow below the review.
Writing a comment is the same as writing a review, except the fact that in comments you can't rate an article.