Apple AirPower charging plate uses Qi protocol, but may not be compatible with other devic...
Apple's AirPower charging plate will charge three Qi devices, and appears to be the first plate that takes advantage of the protocol's ability to deal with multiple devices on the same charger by sensing the location of the device, and only inducing a charge in those locations.

At present, the most common Qi implementation allows for one device to be charged by one base station. As an example, the Belkin charging plate, announced on Tuesday, adheres strictly to that requirement.
There is no specific order for devices on the device, and it appears at this time that a Series 3 Apple Watch, the AirPods Wireless Charging Case, and a compatible iPhone can be placed nearly anywhere on the pad.
This is allowed implicitly by the Qi standard -- it just appears that nobody else has done it the way that Apple is, just yet.
The coils are aligned with each other in either guided positioning relying on the user to place a device in a specific position and alignment, or hardware can be built allowing for free positioning.
Free positioning is generally used in most charging plates, with relatively minor adjustments made by magnetic positioning or other mechanical apparatuses.
Other multiple device Qi charging pads like the Incipio Ghost 220 still have specific locations, and are using multiple coils in one charging unit.

Qi also allows for free positioning to be implemented by inducing a magnetic field just at the location of the receiving coil with multiple cooperative flux generators. Devices put on a plate communicate their location, and the field is only induced under the device by the flux generators operating in tandem.
Apple appears to be using this method for a trio of devices that can be placed in any order, on any location on the pad.
The Wireless Power Consortium trumpeted the release of the technology in the iPhone 8, iPhone X, and Series 3 Apple Watch. In a statement, an executive for the group claimed that Apple's inclusion is paving the way to "ubiquitous access to wireless charging."
Apple cognoscenti John Gruber seems to think that Apple will share the technology it is using with the AirPower with the Qi members -- but there is no obligation for the company to do so.

At present, the most common Qi implementation allows for one device to be charged by one base station. As an example, the Belkin charging plate, announced on Tuesday, adheres strictly to that requirement.
There is no specific order for devices on the device, and it appears at this time that a Series 3 Apple Watch, the AirPods Wireless Charging Case, and a compatible iPhone can be placed nearly anywhere on the pad.
This is allowed implicitly by the Qi standard -- it just appears that nobody else has done it the way that Apple is, just yet.
How Qi works
The Qi standard relies on induction between two coils to deliver power to a device that needs charging. The base station contains a transmitting coil that generates a oscillating magnetic field, which induces an alternating current in the receiving field.The coils are aligned with each other in either guided positioning relying on the user to place a device in a specific position and alignment, or hardware can be built allowing for free positioning.
Free positioning is generally used in most charging plates, with relatively minor adjustments made by magnetic positioning or other mechanical apparatuses.
Other multiple device Qi charging pads like the Incipio Ghost 220 still have specific locations, and are using multiple coils in one charging unit.

Qi also allows for free positioning to be implemented by inducing a magnetic field just at the location of the receiving coil with multiple cooperative flux generators. Devices put on a plate communicate their location, and the field is only induced under the device by the flux generators operating in tandem.
Apple appears to be using this method for a trio of devices that can be placed in any order, on any location on the pad.
Pay it forward?
Apple is a member of the Wireless Power Consortium, and has been since February. It has been using an off-shoot of the Qi technology in the Apple Watch prior to the Series 3, albeit made proprietary by MFi-based authentication.The Wireless Power Consortium trumpeted the release of the technology in the iPhone 8, iPhone X, and Series 3 Apple Watch. In a statement, an executive for the group claimed that Apple's inclusion is paving the way to "ubiquitous access to wireless charging."
Apple cognoscenti John Gruber seems to think that Apple will share the technology it is using with the AirPower with the Qi members -- but there is no obligation for the company to do so.
Comments
Have I just missed the charging rate and power consumption comparisons between this and the dedicated chargers, and what the tolerances are for cases, or have there been none?
Not that it's going to matter a great deal. This is kind of a no-brainer for my wife and I when it becomes available, and we upgrade to the 8, or X, or whatever it is we decided on. One mat on the headboard for both of our phones? Sign me up.
Even if Qi has been out for a while, Apple (or another company) could still cause fragmentation by using nonstandard implementations. Microsoft used to do that all the time in the 90's. I hope this isn't the case - having a universal standard would allow much easier use in public spaces like airports and hotels. How nice would it be to be able to just throw your phone on the nightstand at a hotel? From the article, it sounds like Apple was working with the consortium, so hopefully a multiple-device mat will be part of a new standard. If you extend the theory, an airport could have a 10 foot long counter with one big mat, allowing people to place their phones anywhere on it.
"Working with" and "sharing what's developed" are two different things.
2) For travel, the matrix is starting to get complex. For starters, having an Apple Watch means you need to have an inductive charger. Will the Series 3 charger at least trickle charge the iPhone? If so, then I can likely save on carrying an extra Lightning cable just to charge the iPhone, which I do my plugging into my Mac, which is the only device I bring with its PSU. If it can't use the Series 3 charger then I need to see if it's worth getting my own charger that will work for both items, if it needs to work for both at once or can I pop my Watch on there during showers and my phone overnight to charge them, and if the place I'm staying will offer Qi charging. That last one will become increasingly more common, especially now that Apple has adopted the standard.
Additionally, I've found that charging my Watch on a plane or train isn't a great solution because the low magnetic attraction and the typical jarring of those events. Other possible scenarios could be camping or sailing. A travel Qi charger that will hold the device in some way seems like something in my near future, if it exists.
edit: I can find some basic travel chargers, some with battery packs, but not what I'm looking for. Looking for something that can hold the devices against the charging pad despite being jolted or shaken. A product that could push power out both sides of a travel pad that holds and iPhone on one side and a Watch on the other would be nifty. An elastic step would probably be easiest. No Rights Reserved.
I understand the part about charging stuff at diffent times and places in your house, but for me it would be handy to just drop my Watches and my iPhone in one place when going to bed. Even the AirPods occasionally (I rarely have to charge the case, I've had them since January and charged the case 5 times since then).
It also occurs to me...I've seen people questioning why the name AirPower when the devices need to be placed not the pad and in contact with it. Could it be Apple is using that name so that one day it will work with the rumored 'actual' wireless charging?
2) Devices don't have to be "in contact" with the pad for it to work. Similarly, Apple Pay doesn't have to be "in contact" with the terminal for it to work but I make physical contact with it on pretty much every purchase.
Funny you mention Apple Pay and proximity. I pretty much always put my Watch onto the terminal to pay but I never do with my iPhone, I put the iPhone close but never actually touch (unless in error). I'm not sure why I do that...
This could easily grow into something with more distance, but I would't expect Apple to be first into it, which includes supporting newer Qi standards that will support a larger magnetic field. The smaller the field the less energy is lost in transmission, which I've read—but haven't confirmed—increases dramatically with even additional short distances.