Nobody says that what the IT department does cannot be useful. And it is not about being internal or user-facing. Marketing and customer support are also considered cost centers.
Which is not reasonable in either case. Also, is marketing really considered a cost center in most businesses? I would see that put more in line with sales.
Customer support is certainly treated as a cost center, but it oughtn't be. Mary Poppendieck (author of this article) has a good example in one of her books where the customer support center improved profits by being able to aggregate and identify the majority of customer complaints. This led directly to improvements in infrastructure and delivered systems that reduced overall corporate costs (less rework, customers were happier, more sales).
Those are valid points. My intention was not to discuss the subject but to reframe the discussion. I can see advantages and disadvantages in considering some departments in the company to be providers of services to the rest of the business. But I guess an appropriate, but cynical, definition would be that cost centers are the departments where you can slash costs while hoping there will be no impact on the business...
