Specifically, I worked on the folder organization system that they added to replace the tagging system. This fell out of the API work that I did (which I'm assuming is in private beta right now, but I'm not sure). I also worked on a feature that, while painful as a developer, is my favorite new thing about Gliffy: the basic account no longer has a five-diagram limit! That means for free, you can create unlimited diagrams. The catch is that your diagrams are all public, but I think it's a great way to enhance the functionality while subversively getting their name out to more people.