I just bump to SUMO Paint funny social image manipulation and painting software build on Adove Flex. Sumo Paint is only 900kb flex application that works over internet. When you register at sumopaint.com you can store and share your art work with others. Notice that unlike most online image apps are geared toward image editing, not image creation, but Sumo Paint would like to change that.
Sumo Paint has been clearly created in more relax manner, it is not serious image manipulation program but something that is fun and relaxing.
I will look forward how it will evolve.