Customer is a user who is ready to pay or who paid already.
The customer is a sub-group of users who stand in a monetary relation with a product or service. However, the monetary relationship is different than a business relationship. The latter one could be without any monetary compensation but it could result in an exchange of information, e.g. reading news from an online information service in in return delivering tracking information via cookie. So far information has not been classified as a currency (even it might be considered worth money in some cases). Therefore, the customer term is limited to the monetary aspect.
In addition, the customer term is also affected to the context. If it directly relates to buying or renting an item, the user is considered a customer. However, in case the item is used not in the buying or renting context, the person is a user. For example, in case a person buys a hammer, the hammer gets broken, and the person would like to get the hammer replaced. In this case the person is considered a customer. However, in case the person is using the hammer to drive a nail into the wall, the action relates to the action is not related anymore to purchasing or renting a product or service.
The term “customer” is used in case the monetary aspect of an interaction should be indicated or taken into account.
The next post will look into the term “problem”.