They can be much more impulsive. After all, they don't need to make eye contact with another person, smile, or make a commitment. On the Web, they can take what they want without even letting anyone know they've visited a site. As with e-commerce, they can fill their shopping carts and later abandon them with no guilt or liability. By the way, it is a mistake to think of online applicants as customers, instead of clients.
Customers often shop around to get a particular brand-name product.
Clients, however, are interested in a service, rather than who provides it. In higher education, brand-name products are the degrees from major national universities. Customers of those universities don't care if they could get an equally good education somewhere else at a lower cost. All that matters is the name of the institution on the diploma. But clients will investigate many colleges as they seek services that fit their interests, at the price they want.