Aviary is a great bullet point in Google's argument that the web browser is the modern computer. Why download other software when you can handle all of your work within the browser? The crown jewel of Aviary's suite (also including a music creator and vector editor) is a pretty unbelievable photo editor, one with extensive controls and impressive speed that can easily replace Photoshop for a large percentage of users. The layer-based editor has more than 30 rich editing tools, and while it is not (and may never be) as good as Photoshop for power users, it is a worthy alternative, one that won't show its limitations to most users. Plus, it's free, which Photoshop is assuredly not. Check out the screen-capture Chrome extension as well--it's a nice companion piece to the app.