The ITIL© V3 definition of a service is as follows:
A service is a means of delivering value to customers by facilitating outcomes customers want to achieve without the ownership of specific costs and risks.
So given this definition, how do we know what exactly is a service? As a result of my pondering (and some sauce spilled on my blazer from my lunch) I came to a conclusion. Simply, a service is anything you do to help other people accomplish a goal. In other words it is “work done for other people”.
If a person could accomplish the work themselves, would they need service provided to them? Maybe, but often, they can’t do it as well, as cheaply, etc. As an example, let’s go back to the sauce from my sandwich that sat on my blazer. I don’t know about most of you, but I don’t have the knowledge or machinery needed to dry clear a tweed blazer. So I now faced the reality that I would have to take the blazer to a business that has the capabilities and resources needed to dry-clean my jacket.
Most people would agree that a clothes cleaning establishment is a service business. But why? Because they make it possible for me to accomplish my goal of a clean blazer without the specific costs and risks associated with expensive and complicated dry-cleaning equipment. I can pay them to complete a set of activities that takes my dirty coat and returns it to its clean condition (well maybe even cleaner condition, I can be quite a sloppy eater at times!)
This situation is true with Information Technology as well. If I need to accomplish the goal of communicating electronically with colleagues, then the IT department can help me do that. They can provide a set of technologies and actions that allows me to open an email program, type the letter and send it. Again, I do not need to have the costs and risks associated with owning Exchange servers or email clients. I can simply pay the IT department for that capability and reap the benefits!
So I hope you can see that in the end a service is something that gives us the ability to achieve whatever outcome we need to without all the costs and difficulties that may come with achieving a specific outcome.