From The Purpose Driven Life by Rick Warren...Real fellowship is so much more than just showing up a church services. It is experiencing life together. It includes unselfish loving, honest sharing, practical serving, sacrificial giving, sympathetic comforting, and all the other "one another" commands found in the New Testament...You can worship in a crowd, but you can't fellowship with one.
Jesus ministered in the context of a small group of disciples.
"Each one of you is part of the body of Christ and you were chosen to live together in peace." Colossians 3:15