Dash is a form of digital cash. All transactions in Dash are recorded on a public ledger, or "blockchain." This way, everyone can ensure that the ledger is an accurate an honest account of the currency.
Unlike blockchains such as Bitcoin, Dash offers the desirable properties of paper cash. Namely; instant transactions (InstantSend) and privacy (PrivateSend). Check out www.dash.org to learn how you can benefit from Dash as a consumer, a merchant, or an organization.