The Apple Developer Connection (ADC) Web site has posted "Simplifying Data Handling with Uniform Type Identifiers," a new programming article that explains how Uniform Type Identifiers (UTIs) work.
From the beginning to the piece: "Uniform Type Identifiers (UTIs) are strings that specify abstract types in Mac OS X. For developers, UTIs provide a logical, hierarchical, and extensible approach to the question: iWhat data types does this application support?i If your Mac OS X application creates or manipulates data that may be exchanged with other applications or services, you should read this article. It provides an introduction to supporting UTIs and how your application can benefit."
You can read more on the ADC Web site.