Tap on Glass to run through all of the products for sale, and you can tap your temple to make a purchase. The app has three sections, exploring, purchasing and matching. The latter lets you snap a picture using Glass and you'll be shown items to buy that match the color of what you've photographed. Again, turning to a self-description, Fancy is "part store, magazine and wishlist". If you're lucky enough to own Google Glass, click on the sourcelink to download the app.
If you want to see what Fancy looks like on Google Glass before you install the app, or if (as is most likely) you don't own Google Glass, you can check out the experience by viewing the video below.
source: FancyforGoogleGlass, TheNextWeb via MobileSyrup