Service Learning v. Service

To volunteer (or "do service") is to serve in an unpaid role that helps or supports others.

To engage in service-learning is to combine volunteer service with structured learning.

Both service and service-learning can be effective in addressing community needs and creating opportunities for shared learning.  Service activities are neither less important nor less meaningful than service-learning; rather, they are two activities with different structures and objectives. 
According to the National Commission on Service Learning, service-learning is different from service in that service-learning is "a teaching and learning approach that integrates community service with academic study to enrich learning, teach civic responsibility, and strengthen communities."