I've been reading sort of contradictory reports about this. On the one hand, studies mollpeartree have linked to show that, in general, the more successful denominations are those that make greater demands of their congregants. On the other, a lot of the reports on the fastest-growing congregations focus on the "mega-church" phenomenon, which allows--for instance--people to watch services on a tv screen from the comfort of a coffee bar. Is it some peculiar combination of friendly services but high standards for extra-ecclesiastical behaviour that produces the best results?