On my Mac busy.org uses the Source Sans Pro font. And for that font the bold (<- this is actually also bold,doesn't look like it) and normal are nearly indistinguishable. 馃憞
I've looked into the source code in fonts.less file, and it makes sense "Source Sans Pro" regular font weight is loaded only. Also "Whitney" font is supposed to be used as base font. Not sure why it isn't though.
Posted on Utopian.io - Rewarding Open Source Contributors