I'm not sure how sustainable this model is. Especially when a reader browses via a link aggregator and therefore reads news articles on many different websites. I doubt most people want/can afford a subscription on dozens of different news outlets, as that'll quickly add up to a triple-digit monthly bill.
Something like Flattr, but maybe non-optional, would be better. Pay a fixed monthly fee and split the payment between all sites you read articles on (maybe based on how many, or reading time or whatever).