Floating shelves are one option used in many homes to display personal items in a clean and uniform way.
Floating shelves appear to have no visible hardware holding them onto the wall, as they are attached with hidden screws and hardware. These shelves appear to "float" on the wall, thus the name. Generally considered strong enough to hold a variety of items, this type of shelf is traditionally meant for small and light items. The shelves can create a sleek and modern look, considered to be "minimalist" in style.
Choosing a place for floating shelves is a matter of taste and aesthetics. Floating shelves can be situated above furniture such as couches, but you need to think about what will be on the shelves. You wouldn't want the shelf to pull away from the wall over time and dump it's contents onto the heads of your guests. Also, if the items you store on the shelves are used often, it can be awkward to access them with people sitting on your couch.
If you are into feng shui, shelf placement is extremely important. In this philosophy, items stored above your head can contribute to depression and lack of energy, because overhead storage is thought to be oppressive. So from a feng shui point of view, shelves above your couch are not a good idea.
Decorators suggest when using floating shelves, place them in sets of two or three. More makes the wall look cluttered, less makes the wall looking lonely. So if you don't have enough space above your couch for several floating shelves, you might want to put them someplace else.