What I mean is that the church does not exist to serve itself; its own instutional growth, survival or health. The church exists for others. The church is an agency with the purpose of the transformation of the world, the building of the Basileia (realm) of God, the Beloved Community.
A church that does not concern itself with the outside world is failing to be missional and failing to be church.
The church is in the business of salvation/healing/enlightenment. Salvation is distorted if it is too individualistic ("personal wholeness" or "getting into heaven") or too communitarian (all that matters is the next piece of political legislation). Missional church seeks to change lives which may or may not involve an invitation to go walk with us in our spiritual community.
Being missional means being immersed in the surrounding culture, understanding it, understanding the lives of those outside the church, and discerning what is life-giving and what is not in that culture.
Being missional means facing outwards, not inwards.