David Rayners wrote a MovableType Dropcash plugin and then held it for ransom through Dropcash until he raised $30. Though his PayPal account is new, and he couldn't accept the payments to reflect on his Dropcash page, he released his plugin as soon as he hit $30.
I think it's a great way for people to get paid for their work for specific things, rather than general tip-jars that nobody seems to ever want to drop money into.
Also, Dropcash was mentioned in this Guardian story. Along with some words from me.
I've never used the word 'appeals' in that context. Strange how it showed up in there. Also, you don't need a TypePad blog to be able to raise money, just a TypeKey account and Jason Kottke co-created it with me.