It's web-based so there's nothing to download. You just go to the website and sign up for 2 gigs of storage where you upload your pictures, and then you can create albums and organize your photos, then edit them however you see fit. It feels like a water down version of Lightroom and it seems powerful (and simple) enough to do the trick for most people out there.
Just thought I'd pass the word along to those who are looking for a cheap alternative to PS. https://www.photoshop.com/express/index.html