I registered Popfly long time ago, but I am not a artist and not fond of design web pages. That is why I do not visit that site much. But today I find Popfly Explorer, an Addin for Visual Studio (Express Edition supported).
What catches my eyes is that I can upload projects to my Popfly space easily. In this way, I can store all projects online.
What is Popfly? I do not understand well now. But I will continue to explore in this field.