Anyone else heard of and/or used Flattr or similar payment sites?

Other than needing a significantly critical mass to be useable and the usual financial bungling and tricksters, are there good reasons to not support them?

I'm really wanting to know economic contemplations and opinions of them rather than answering my unsophisticated questions.

Erg! I didn't read my links! they seem to have little to do with flattr-esque ideas.

Mobimoneybox a slightly different idea from what I gather more about the transaction than the distribution.

Bitcoin looks to be interesting but haven't followed through