The best thing about this software, apart from being very user friendly, it's that you can use your content easily to create new applications without any programming skills needed! It took me some time before I could understand how everything works but now it doesn't take long at all if you know what do want or need out of an application.
Nothing really in particular - just as other people have mentioned here already, there are not many things one needs to learn when using dynaSign online since almost anything imaginable comes with it (from videos to slideshows). You don't even need hosting because most free features include web hostings so the only think we had was getting our logo designed correctly which wasn´t too difficult either. We used dynaSig online mostly for creating presentations.