ColdFusion components (CFCS) are another feature that's new to ColdFusion MX. They are more than just a series of tags; they're a whole new way of creating reusable code as well as an approach to developing ColdFusion applications.
ColdFusion components bring to the language a new and exciting approach for code reuse as well as development practices that are more akin to object-oriented programming practices than previous code-reuse paradigms in ColdFusion. CFCs give ColdFusion developers an unprecedented level of functional abstraction and encapsulation as well as standardized interfaces for a variety of access methods, including SOAP-based web services.
CFCs, like ColdFusion's other code-reuse methods such as CFML tags, cfincludes, and user-defined functions (UDFs), enable developers to create functions that can be called from wherever you need them in your ColdFusion application. CFCs go a step further by adding concepts such as inheritance and introspection, allowing for a much more robust code-reuse model in large-scale applications. They also offer methods to integrate with not only other parts of your ColdFusion applications but different applications altogether through web services.