There are four main levels on which a central persona can communicate with a community or a subset of its members.
Generally this is top level, one-to-many communication around which the community is naturally organized. The broadcast level often consists of a blog, TV show, video blog, a welcome message, announcements, mailer, or a splash page.
The broadcast level is the primary place where a central persona expresses opinions and shares information. It is also where a central persona can reflect a simplified image of the community back upon itself.
The structural level includes the organization, format, rule sets, design and layout of anything within the boundaries of the community. Changing any of these elements can be considered communicating on the structural level.
Communication on the structural level can be used to:
:: signal new opportunities for community activity (opening a “current events” forum, adding voting, comments, etc..)
:: alter the framework of community identity (creation of sub groups, rankings, private areas)
:: accommodate wide spread requests or complaints
:: co-opt rogue sub groups (creation of new labels/ status to accommodate the group)
:: intervene in a crisis situation with a small group of members (changing status, modifying avatars, banning)
Structural communication is the most direct display of power available to a central persona... e.g. “Playing God".
The community level includes all the tools that the community uses to communicate: threads, comments, reviews, gallery uploads, response videos. A central persona should avoid communicating at this level if it is possible to use a structural approach. For example it is better to append an existing comment/thread with a remark than it is to post a new/separate comment under the moniker of the central persona. In my opinion the central persona is not a member of the community, but rather is part of the structure of the community.
The personal level includes any direct communication with a member or small group of members that is not visible to the rest of the community. This is best used as a means to organize high level community members, or to reach out to valued community members in times of crisis. A central persona should avoid using any personal level communication beyond valued/trusted members.