The definition of an IT service has certainly evolved: IT Service   (ITILv1) :     A set of related functions provided by IT systems in support of one or more business areas, which in turn may be made up of software, hardware and communications facilities, perceived by the customer as a coherent and self-contained entity. An IT service may range from access to a single application, such as a general ledger system, to a complex set of facilities including many applications, as well as office automation, which might be spread across a number of hardware and software platforms. IT Service   (ITILv2) :     A set of related components provided in support of one or more business processes. The service will comprise a range of   Configuration Item   ( CI ) types but will be perceived by   Customers   and   Users as a self-contained, single, coherent entity. IT Service   (ITILv3) :   A   Service   provided to one or more   Customers , by an   IT Service Provider . An IT Service is base

A Service Catalog is one of the first assets that an organization should build when initiating their Service Management program.  After all, how can you manage services if you do not have a clear understanding what services your IT organization provides? Unfortunately, many organizations struggle with obtaining agreement on the scope and definition of end-to-end, business enabling services.  If left unchecked, these struggles can turn political and widen the divide between IT and the business as well as cause conflict between internal IT units.  To avoid some of the potential challenges in service definition exercises, here are some helpful suggestions: Set the stage by providing IT staff with a chart of business processes and begin integrating business vocabulary into service parameters ("Order Processing" not "Ecommerce").   Have business stakeholders conduct "lunch and learn" presentations that educate IT on how each unit uses IT Services.  Start