I have a Flattr account, but I only use it for regular contributions to a couple of open source projects, since I never see a button anywhere.

Being in the content game, it's because it's totally not worth littering pages for the 5 cents a month it'd make.

I'm hyperbolizing, but even if it were $100/month, it wouldn't be worth the space. What this space needs is someone with deep pockets to subsidize the publisher growth until the critical mass of users is reached.

Micropayments have been the obvious - to me - solution for this problem since I got on the internet in 1997. Still never seen it employed anywhere. Yes, heard of flattr. Never seen a single site that uses it.