It could be solved by going the infrastructure route.
I'm thinking a free ISP with ads instead of monthly payments as a source of revenue. The ISP would have a whitelist of websites that are available, everything else is blocked.
Businesses would pay a monthly fee to the ISP to be added to its whitelist. In return, ads would be displayed after users spend a certain amount of time on their website, with ad revenues going directly to the website.
The free, ad-driven ISP would start out as an experiment in a small area. It would be available via public WIFI to primarily serve mobile devices without cellular data plans.