The ability to see your pages before they go live to your customers.
By clicking the Preview button on any page that you're editing, you'll get a link that can be used on any browser on any device to see your pages as your customers will see them. A QR code is also provided which you can scan on your mobile device and see the preview that way.
Any changes you make to your pages within the page editor will be updated instantly on the preview as well.
"I previewed my page and when I changed where a Tastic was placed on the page, I could see it change instantly on the preview!"
For more info, see the Previewing pages article.