Touchpoint is every point of interaction, internal and external, seen and unseen. Although touchpoint is countless, it can grouped under three categories: People (P), Information (I) and Deliverables (D). Why three, but neither less nor more? There is a natural relationship among people, information, and deliverables: people produce/hire deliverables based on information available.
In Overpromise and Overdeliver, Rick Barrera mentions three types of touchpoint: Human, System and Product. Barrera's touchpoint system is external-focus, and may not be able to apply to internal business settings. If touchpoint is every point of interaction, then there are both internal and external touchpoints.
In an internal organization, people refer to leaders, managers, and staff. Staff deliver results based on instructions given by superiors. Without such information, whatever staff produce will be irrelevant to both internal and external needs. When needs are not met, it will usually result in lose-lose outcome. Information also affects execution quality. People are always the most important asset. People without the right attitude will never get anything done. Even if the deliverables are produced, they are going to deliver negative experience.
In an external market, people refer to customers, suppliers and competitors. Customers hire deliverables based on information available to them, either via marcom or word-of-mouth. Of course, without needs, everything means nothing. The advertisement may not serve any purpose at all when there are no needs, but it has to be at least there to facilitate the hiring process. Needs can be created after all. Seller also has to be able to discover the needs. That is the most important piece of information.
The more the touchpoint, the deeper the relationship.