EXTENSIBLE CONTENT SERVICE FOR ATTRIBUTING USER-GENERATED CONTENT TO AUTHORED CONTENT PROVIDERS

A method and system allows a user to add content to a displayable content container (e.g., web page) that specifies at least one modifiable portion, where the modifiable portion is served by a server operated by one entity, but provided to the server by a service operated by another entity. The modifiable portion is attributable to the one entity and remaining content in the displayable content container is not editable by the users. Other features, such as user authentication mechanisms, are also described herein.