You are trying to install or open an app that didn't come from the Mac App Store but you got a message saying App can't be opened because it is from an unidentified developer. This is how you bypass it.
Last time we created an overlay pattern image using Photoshop. Today we will use that image on a website to give the full screen background a pattern overlay.
This is how you add your favorite websites shortcut to your iPad or iPhone running iOS 7. It's a really useful feature if you are accessing some webpages frequently.