OK, well here's my more in-depth take on it! I work for an Enterprise Software company who's 'customers' are made up of almost entirely global 2000 companies. We always refer to the people we sell our software to as customers. In technical support, they service the customer. In professional services/consultancy they service the customer. This is because to utilise these services you must already have bought the product.

It just does not sound 'right' to use the word client in the empeg context. Although the company is still in the early adopter phase, they will soon be facing the chasm, as defined by Moore in 'Crossing the Chasm'. Once over the chasm and into a more general marketplace I feel that the client metaphor will not serve the company well.