In order for a content rating system to be successful, it has to

A successful content rating system derives its value from user participation and the context provided by a community. For ratings to be meaningful, they must be relevant to the users who consume them. A social component, where users can see ratings from peers or a trusted community, enhances engagement and adoption. This "wisdom of the crowds" approach, often seen in folksonomies and social tagging, is effective only when the "crowd" is a relevant community of interest, ensuring the ratings are contextual and useful.

B. The specific scale is arbitrary; binary systems (like/dislike) or 5-star systems can be equally or more successful depending on the context.
C. Commentary is a feature of a review system, not a mandatory element for a rating system's success. Many successful systems use simple ratings alone.
D. Limiting ratings to subject matter experts creates a bottleneck and is contrary to the principle of leveraging broad community input for success.

1. Mathes, A. (2004). Folksonomies - Cooperative Classification and Communication Through Shared Metadata. Graduate School of Library and Information Science, University of Illinois Urbana-Champaign. Section 3.2, "The Value of Folksonomy," discusses how value is derived from the aggregation of personal and community-based organization.

2. Marlow, C., Naaman, M., boyd, d., & Davis, M. (2006). HT06, tagging paper, taxonomy, Flickr, academic article, to read. Proceedings of the seventeenth conference on Hypertext and hypermedia. p. 33. Discusses how social factors and community interest motivate users to tag content, which is a form of rating/classification. DOI: https://doi.org/10.1145/1149941.1149949