On a quick read, the article doesn't talk about the licensing for the free fonts. Several free fonts I've liked are free for personal projects or websites, but are chargeable for commercial projects - and one should be careful about selecting them.
Secondly, fonts are very easy to pirate. The commerical fonts (eg. TypeKit fonts) can be copied and reused with a bit of HTML+CSS knowledge. Anyone know of a way to enforce the font licenses?