Do not separate yourself from the community. (Pirke Avot 2:4)
It never hurts to have staff members participate in the Blog Team, but try to create a congregant-driven enterprise rather than a staff-driven one. Invite your team to create the content and rotate staff members in to share their own stories.
Many congregations begin this process with a blog by the rabbi. There's nothing wrong in this people usually want to hear more, read more, or connect more with the rabbi. A well-done "rabbi blog" can generate comments, interaction, discussion, and interest. A great example of a "rabbi blog" is by Rabbi Paul Kipnes of Calabasas, CA (rabbipaul.blogspot.com). He shares his own experiences, invites readers to comment, and uses creative methods to bring congregants in. For example, for each day of Chanukah, he gave "cash for comments" tzedakah in proportion to the number of comments received on a post.
A successful rabbi-blog can become a congregational blog by inviting others to post. Once the congregation is accustomed to the idea of a blog by the rabbi, then it's a good time to bring in a Blog Team, and expand the scope and substance, and thereby creating a congregant-driven community.
Beyond the rabbi, however, your congregation is a wealth of material for a blog. At the beginning, set up a schedule and invite all members of your staff to participate. Ask the congregational educator to write about classroom experiences and projects, the cantor to write about musical selections for upcoming events, the executive director to describe some of the inner workings of the congregation. Invite support staff to share their stories; what brought them to work in the congregation, how do they see their role as a part of the larger whole of the congregation? As a staff, brainstorm different ways in which each staff member can share more of their job and their interests with the rest of the congregation. Remind staff members to ask questions and solicit responses in order to keep the flow of conversation going.