I agree but Flattr does provide an interesting approach. With them you set aside a set amount per month you want to donate. Then when you tip a site it gets a proportion of that amount based on the number of tips you made in the month. This way you cap your total spend per month. You could do this manually of course. Maybe sites could start a system of including a bitcoin address in a file at a common location in the URL space.
Dogecoin is doing a good job positioning itself as the internet tipping currency, as far as I know there isn't a dead-simple way of doing it yet though.
