It's very hard to quantify attention. And also, is that the most important? Quantifying a reward should not be given to an algorithm. That's the only reason why things like this[0] happen.
For me the best way is either a Netflix style network (like safari books), or something like [1].
[0]: https://unhashed.com/cryptocurrency-news/are-fake-websites-a...
The reward distributed to them is paid by you. Your balance accumulates either through opting into ads (advertisers pay you to intrude), or you can buy Basic Attention Token yourself (like via Coinbase) and top up your wallet.
Brave is doing exactly what it sounds like you want.