BLOG POST: A quick thought on "church membership" and titles at http://thesidos.blogspot.com/2012/03/quick-thought-on-church-membership-and.html
Love this quote from the post:
If you love one another, "membership" is completely unnecessary.
If you don't love one another, "membership" won't make a difference anyway.
and this one:
There is no greater title in the church than "brother". That should be honor enough for any Christian man.