It may describe the environment, geographic and otherwise, in which you operate. A vision may also change, but it should give you a sense of direction. Non-profits need to describe, in marketing terms, what and who their target market is. This can be confusing, as sometimes the target is the group being served and sometimes it is the people or organizations that provide funding to deliver services. The better the non-profit can describe the various targets, the better the organization can provide services that matter.
Targets can move, grow larger and can disappear.
Keep a laser-beam focus on your targets. Candidly, this is an area where most organizations fall down on the job. Every year I see the Girl Scouts in front of the local supermarket. Education can take in many forms, including brochures, press releases, feature stories, direct-mail pieces, word of mouth, advertising, public service announcements, television and radio interviews, public speaking engagements, annual reports and the like. Education must be consistent and in must be in sync with the organization's targets.