Anypoint Data Gateway allows users to easily integrate Salesforce with external legacy data sources like SAP, Oracle, and SQL. It provides a simple point-and-click interface to access and wield Salesforce functionality on external data. Data Gateway supports instant connections to various back-end systems, eliminating the need for separate design environments or extensive user training. It is installed via Salesforce AppExchange and its designer interface allows quick configuration of gateways to external data sources and creation of new objects.