Strictly speaking, TOM is a data model for describing a wide variety of data formats. TOM can be used as the basis for many value-added applications. On the Web, TOM is best known as the basis for conversion services like the TOM Conversion Service . This represents a very important application of TOM, but TOM itself has lots more to offer underneath the surface as well. In TOM, documents and other data are modeled as objects .
All objects have a particular type , that reveals what can be done with an object.
There are two important differences between TOM and most object-oriented systems. First of all, TOM treats all data, from whatever source, as objects. Objects don't have to have a particular representation, or be managed by a particular program or database. A message being transmitted across the Internet is just as much of an object as a strongly typed structure in compute memory. TOM is also stricter about subtyping than many other object-oriented systems.