The roles in a Smart Links infrastructure are:

• The Author

The author creates content and posts it on the Internet.
The author's role is to define a title, a description and tags for the posted content. Smart Links then use this information to classify and retrieve the content.

• The Authority

The authority is either the home of the content or a service provider for the author.
Its role is to validate and supplement the metadata provided by the author, store it in a database together with a link to the content and respond to queries.
The authority shares its information with other authorities to spread the load and speed up access.

• The Aggregator

The aggregator is an optional part of the Smart Links infrastructure. Contrary to an authority, the aggregator does not maintain its own database, instead relying on authorities for Smart Links updates.
Its role is to respond to queries. If a query is ambiguous it can answer it with aggregated results from different authorities.

• The User

Finally, the user is the client of the Smart Links service.
The user follows Smart Links or makes queries to retrieve content from an authority.