A new term is sweeping through affiliates and publisher land recently. There has been much hype surrounding the Times Pay-Wall with other major newspaper content brands already queuing up similar paid content walls.
The benefits are obvious and numerous for the publishers themselves but how is it playing out with the consumers and advertisers? No doubt a pay-wall can't hurt quality or engagement but there is an uphill fight to get anywhere near the scale of pre pay-wall unique visitor numbers.
The third way - is the reg-wall or 'content unlocking' as they call it in the States. I think the reg-wall offers the perfect balance of engaging interested users to sign-up for additional content (and advertising of course!) without putting too many users off meaning you can scale up effectively.
I haven't seen anyone get this right yet, but the ones that do first are bound to reap the biggest rewards.