Having learned more since then (and having written about it), I know better.
Like the name says, Power Over Ethernet (PoE), also known by its IEEE standard ID, 802.3, is about providing power over Ethernet, that is, over local-area-network cabling, similar to how many USB devices can get their power through the USB cabling -- in both cases, assuming that it's a "powered" port, meaning somewhere along the line, something is "injecting" power alongside the data.
If you're familiar with powerline networking -- using the electrical wiring in your house also to send data -- it's like that in reverse.
WiFI is useful when it's expensive or inconvenient to run network cabling -- to all those notebooks and smartphones and tablets in airports and coffeehouses and libraries and BoltBuses, Megabuses, LimoLiners, and some trains, in offices and homes; to connect printers, electric power meters, and so on.
PoE, same reasons, different scenarios: When it's not as big a deal to run network cabling, but expensive or inconvenient or unsafe to run wall-current power wiring, especially if you're a small-to-midsize business and don't have in-house electricians. The amount of power that can be provided via PoE is enough for many low-power devices, like wireless Access Points, VoIP desksets, security webcams and other security/environmental monitoring, even enough power to charge a smartphone or other small mobile device.
I've thought of trying PoE out here at home, as a way to move the WiFI router out into the hall without having to string a power extension cord.
So when I see a PoE press release, article or product, I don't skip over it, I like to see what's new... and I've seen two in the past week or so.
Microsemi Doubles Reach for Power-over-Ethernet Midspans
Microsemi Corporation recently announced a single-port PoE extender that doubles the powering reach of its PoE midspans to 200 meters, meaning it can deliver its 25.5 watts of power across a cable up to roughly 600 feet long, instead of 300, and also supporting up to 1Gbps of data.
According to the company, they're the first to do this for the 25.5-watt level, everybody else is still only able to push 15.4 watts that far.
So for example, you could string network cable to put a wireless Access Point in the middle of a field... or a Pan-Tilt-Zoom network camera at the end of a parking lot, without the expense of running a regular power line that far, and the cost of making sure it's safe from weather, traffic or other menaces.
And this is a "mid-span" device; it doesn't eve need local A/C power, it can take power coming in from a PoE-powered Ethernet cable as its power source.
SkinnyBytes Launches Touchscreen PoE Computers
SkinnyBytes recently announced PoE-powered All-in-One (AiO) computers (computer/screen combo units), with touchscreens in display sizes fro 8.9 inches to 18.5 inches. Thanks to low-power Atom CPUs, LED backlit displays, solid-state drives, and fanless cooling, these machines can make do with the lesser amount of power that PoE can provide, rather than that pesky, expensive-to-install, comparatively-dangerous AC electrical power.
According to SkinnyBytes, "Eliminating the need for installing an AC outlet can easily reduce the cost of installing new computers by 50% or more."
Also, the company claims, PoE computers use 90% less power than a traditional computer. Even if that number is an extreme case, these computers can be put where it's expensive to run AC power, or you don't want to, because there's coffee and other liquids, or you're dealing with the public, perhaps students, and want to minimize what can go wrong.
For SMBs, Power Over Ethernet can be a, ahem, powerful cost-saver, and opportunity enabler. And I belatedly apologize to whatever PoE product I originally saw that I didn't take seriously.