Wires cramp your style.
Tired of stringing Ethernet cable over doorways, under carpets, and down the hallway? Power-line networks use the wires that already exist inside your walls, tapping into the same circuit that moves electricity from point A to point B. It's about time your living room looked like a living room, instead of NASA Mission Control.
Too many walls for Wi-Fi.
Sure, wireless networks work well for some people, but there are some venues where Wi-Fi simply doesn't reach far enough to provide reliable service across your entire home. If thick or heavily insulated walls don't cut into wireless strength, there's a variety of household devices, from microwave ovens to cordless phones, that can cause radio-frequency interference. Neither is a problem with power-line adapters; as long as you have a spare AC outlet in a room, you'll be able to get network access there.
Get the best of both worlds.
If you're looking to turn that spare bedroom into an office, don't fret over rewiring the east wing: just pop a new adapter into a spare power outlet, and you'll be good to go. You're getting the benefit of an always-on wired network, together with the clutter- and hassle-free joy of Wi-Fi.