The blurry, transparent background in Notification Center, Control Center, Spotlight and other more options menus on iOS 7 device can make reading experience rather unpleasant.
If you want to make a clean install of the new OS X Mavericks or even the older versions of Mac OS X, than I strongly suggest you to create a bootable OS X key or a drive.
Microsoft Word allows you to add the comments to text, images or basically anything included in the document. It's a great way do review a document and suggest the changes that should be made.
Some websites overlay their photos and images with another blank image. But there's an easy way to download those pictures if you are using Google Chrome browser.