Here at DIY Drones, we adhere to open source principles wherever possible. That means we aim to share (that means post it, not make people ask for it) code, schematics, PCB files, parts lists, instructions, and algorithms for every project featured here. In practice, that's not always possible (not all project have PCB files; not all projects need schematics), but it's our philosophy.
Is that "open source"? In spirit, yes. But in letter, it's more complicated, because hardware is more complicated than software. We can't GPL a parts list, and the license that we do use for this site, a Creative Commons "Attribution" license (use/modify what you want, but give credit), doesn't have the same viral characteristics of the GPL in the sense that people who use our intellectual property are free to keep closed their "derivative work" if they want.
This is all a bit messy and complicated, but fortunately Phil Torrone of Make Magazine gave a great talk on Open Source Hardware at Etech that helps explains all this, and it's now available