If someone outside tried to parse the text following that tag, they would not understand the value. Partner schemas are what you would develop to share information between business partners. For instance, if Corporation A were teaming with Corporations B and C on a project to create a new military plane, they would develop a schema for that plane. They could call the forward section something that would mean something to them, but it might not make sense to the rest of the design world. They could also categorize groups of design drawings so that they could be automatically parsed and distributed to the right teams via an XML-enabled distribution engine.
Industrywide schemas are what a whole industry works on together.
For example, the insurance industry has come together to form a group called Acord. That group is setting the schema for all insurance companies that want to use it. Acord hopes that developing a standard schema will help companies that embrace XML share information gathered on forms. It will also help them avoid barriers created by proprietary software. There are a bunch of industrywide organizations cropping up that are focused on the travel industry, libraries and the IT supply chain, just to name a few.