Communicating Value to Volunteers

What is it you do (I'm talking intentionally, not haphazardly) to communicate to your volunteers that they are valuable? Mark Waltz blogged about Patrick Lencioni's Catalyst session on this very issue. According to Mr. Lencioni, "People want to know that their work and personal contribution is relevant to what's going on in the workplace – or church." Here's the rest of the writeup.