This. Paying taxes is (at least in western countries where i know a tiny bit about academia) sufficient to support the authors. If you want to go beyond that:

This. Paying taxes is (at least in western countries where i know a tiny bit about academia) sufficient to support the authors. If you want to go beyond that: reach out / blog / tweet / etc about papers that peek your interest. If someone else wrote about a paper of mine, I'd be over the moon!