Dumpr, an online photo effects application. You don't need to sign in to Dumpr to create your project.
What was really cool about Dumpr what that you could not only easily save your project to disk, you could just as easily save it to your Flickr account. After doing that you could use Flickr to post it to your blog. All this was pretty much seamless except for giving permissions to each application to access your accounts to do so which worked very smoothly. It looks like I will have to edit the blog post to insert the link for Dumpr, because I can't see any way to do it in Flickr's interface, but how cool is that anyway. Great the way these apps can work together.