@graeme_p webOS is more opened than Android. If you want to start hacking it you just put your phone in developer's mode and start hacking away. There's no jailbreaking or complex means of opening the hood of your phone to start playing with the internals.
There is a very active homebrew community that has unearthed the hidden virtual keyboard that was included inside webOS within two days of the phone being released. There's even an app to boost the processor speed of your phone from 550 to 800 mgz and anything in between.
People were able to hack webOS to make it open OVI apps from Maemo. A Firefox dev was able to port the Android Firefox app to webOS in two days. People are currently working on porting Open Office. Most apps written in C or Objective C can be ported within days to webOS (mostly iPhone apps, such as games). That has led developers like Gameloft, EA and many more to port all of their games as is to the Palm Pre with minimal changes. Android doesn't allow that.
With Android, can you change the factory settings of the phone's maker? I mean can you remove HTC's Sense UI and use something else? When AT&T limits some functions on their Android device, can it be hacked back to reintroduce all the missing features?
webOS is actually more stable and a much more mature mobile OS than Android. Basically webOS is what Android should have been and why Google created Chrome after they witnessed webOS last year. Android doesn't have the same elegance and stability of builts. How many variants of Android are running around on multiple handsets? On webOS all users use the same release. On top of that, Palm has been able to multiple updates (10 +) through the cloud of their webOS on different models, different network, different countries smoothly. At anytime, users are using the same OS version. No other company was able to do cloud updates as effectively on so many carriers and languages. When until the HTC Hero users get the latest Android release? There's been an average of one update per month from Palm since June.
Maemo is open too and a good mobile platform, but it has no elegance in its design. It's just a regular desktop interface. I had a Maemo device - the Web tablet, and although it could do multitasking, it taxed the system. The interface had nothing original. Just like Android, it relies on widgets and a complicated sub menu interface.
webOS relies on the card interface. It's a gesture based interface that does more with multitouch than the iPhone. First, there is a gesture area under the screen, just like on a laptop. Swipe forwards are universal forward buttons, swipe back are universal backward button. Swipe up pull the menu bar within an app and so on. Apps are opened in cards. There is no hidden widget running that the user does not know about and struggle to shut through many complex menus. If the card is up, the app is running, if you want to shut the app, you swipe it up with your thumb and its dead.
Also, with the cards, it's real multitasking. Unlike Android and iPhone OS 4.0, apps continue to run in the back when you switch apps (except apps that run video games or Flash). So you can download a heavy Web page while responding to an email or using Google Maps while using Pandora, while uploading a movie you recorded to YouTube - all at once. There is a famous video on YouTube where the user has opened 50 apps at once and they are all running. He stopped at 50 because there was no point going forward. The phone did not budge or die. It just kept running the 50 apps. That's real multithreading. This phone is the closest to the experience a desktop user can have.
And that's why people have been dying to see webOS on a tablet/slate computer. There's so much more that can be done with the OS on such as device. It could realistically replace a computer.
Palm's problems has been lack of money and a lack good advertising. But its product is the most innovative. It's the only phone that can charge itself wirelessly. You put your phone on its Touchstone base and it charges itself without you plugin any wires into it. Once you start using the Touchstone, there's no way going back. It's all these innovations that has made Palm such a good catch for HP, along with its solid patents' holding that more than match Apple's. Apple hasn't sued Palm because it knows it infringes on so many Palm patents that it would be a mutually assured destruction on both companies. Palm has the patent on the search by initials, on the proximity sensor, on the light sensor that adjust the phone's brightness with sunlight, it has the patent on the airplane mode that everybody uses. Palm never went after Apple or other mobile makers to force them to license its patents, but with a bigger and richer owner, like HP, Apple, Microsoft, BlackBerry and Google may have to start paying licensing fees on all the patents they have breached for years.