One of the key advantages of service applications is their ability to be consumed on an a la carte level. Use the service only as you need it. Extending this paradigm further, service applications are similar to services in a cloud. Use what you need, no matter what farm you are using.
This gives organizations the ability to pool their resources effectively. An example of a resource that could be shared is content types. Many organizations are ISO certified and as such they are required to collect particular information with regards to their documents. A content type can be set up to which custom fields are assigned. For example, we could create a field called Safety Training Date and assign that to the content type.
As the SharePoint installation grows, more web applications and site collections are created. The organization does not want to recreate the content type that contains the field safety training date in each farm. By publishing the metadata service...
