One of the things we hope http://TipTheWeb.org/ will be good for is offering a way for creators of open source tools and useful web services to get money from the people who use what they've created, especially for things that would be hard to build a full business around, but which still have significant value.

Much of what's great about the Web is exactly that: valuable, published for free access, not the basis of a full-time business, yet definitely worth supporting.