Intangibility is used in marketing to describe the inability to assess the value gained from engaging in an activity using any tangible evidence. It is often used to describe services where there isn't a tangible product that the customer can purchase, that can be seen, tasted or touched.
Other key characteristics of services include perishability, inseparability and variability.
Marketing Implications
When a customer is buying a service, he perceives a risk related to the purchase. In order to reassure the buyer and build his confidence, marketing strategists need to give tangible proofs of service quality. Because of service intangibility, consumers are less likely to switch brands or try new ones.
References
Intangibility Wikipedia(Text) CC BY-SA