Community facilitators or facilitators in a community are those members of the community who help you run it. They can be officially appointed or indirectly be so heavily involved with the community that they can be considered Superusers or Superfans on the verge of becoming administrators.
In some communities, the two terms - facilitators and administrators - can be synonymous with each other and often serve the same purpose. But in larger communities, facilitators are often those who help overlook certain aspects or projects within the communities. Their responsibilities also include - as the same suggests - facilitation or easier execution of programs or events.