A Content Type hub is a feature that publishes content types to other site collections. In SharePoint 2010, the content type can be defined once and managed from a central location. No longer is the content type creation in a site collection a silo of work that must be repeated in all the other site collections (and web applications) where it must be available.
Content types can now be shared across an organization.
The business rationale for this feature is the ability for an organization to create a central repository of content type assets. Then, as other site collections need to leverage these content types, they are available.
A popular feature is the publishing website. It is not uncommon to create different article ...