If you want to share your broadband Internet connection throughout the house, the obvious first choice is a wireless network. But wireless isn't always practical. Sometimes you need wires—like when you have a desktop computer with no WiFi adapter in another room, or there's radio interference blocking the WiFi signal in parts of your home. Or maybe you just aren't getting enough bandwidth for moving around big chunks of data like high-definition video and music files.
Fortunately, you don't necessarily have to start pulling new wires through your house to do that—a technology called "Broadband over Power Line", also known as HomePlug AV, will let you run a high-speed network over your existing electric wires. Just plug adapters into wall sockets within your house, plug your router into one and computers and other devices into the others, and you've got an instant network.
The technology has been around for a few years now, and has been steadily improving. For example, Belkin's Powerline HD adapters advertise a throughput of up to a gigabit—that's 1000 megabits, almost 10 times as fast as the fastest WiFi-based networks. The actual speed depends on a lot of factors. But even over long distances within your house, the Powerline connection will be many times faster than your Internet broadband connection.
HomePlug AV can be used with any device that has an Ethernet jack. That includes most personal computers, and an increasing number of high-definition televisions and Blu-ray disc players that use Ethernet for accessing Internet streaming video services like Netflix.
Belkin's Powerline HD costs $150 for a pair of adapters. That's certainly more expensive than running a length of network wire through your house, but it's a significant savings over the cost of having an electrician or other home installer come and snake wire through your walls.