The answer is embedded in the term: denial of service. The motive of a DDoS attack is to prevent the delivery of online services that people depend on. Financial institutions, gaming and e-commerce websites are among the top targets of DDoS attacks, as are cloud service providers that host sites or service applications for business customers. Even a brief disruption of service delivery can cost an enterprise millions in lost business, not counting the after-effects of alienated customers and reputational damage.