I'd love to know what the developers of Picnik think of Adobe's new Photoshop Express. It doesn't have the flexibility of Picnik, but the design is excellent. In particular, the way it lines up variants to click on makes it very easy to see what you're going to get when you use tools like white balance, B&W, auto-correct, etc. I also like the way you can deselect changes you've made based on type, rather than having to go back with Undo in linear fashion.
No doubt Adobe will use Photoshop Express as a way to promote its paid applications.