A lot of what's in today's mobile OSes came from webOS. Cards for multi-tasking. The full-screen gestures introduced with the iPhone X basically came exactly from webOS. Samsung copied its Touch2Share years later. It even had some advanced sync features that no one has yet to properly copy.
Now-a-days, Android and iOS kinda take turns copying each other and mobile webOS is mostly a relic -- but it was from a time when phones didn't exist to suck up your data for advertisers, so it remains charming and delightful.
A lot of the WebOS UI/UX DNA ended up in Android generally and in Material Design specifically because Matías Duarte went to Google as Palm imploded. He was a VP at Palm and is now VP of design at Google.
Or that was the hope, but unfortunately a lot of what made WebOS good was the synergy between his team's excellent design thinking and the clean, practical, well designed platform underlying it. Android is a mess because it tried to reinvent the wheel everywhere from day one, and then Google took over. Which means barely 15 years later it carries multiple Windows' worth of legacy garbage. They've done some lovely UI design, but they have been unsuccessful making that type of work anything more than skin deep.
It was revolutionary in how it was just the modern OSX UI on your phone.
App menu was always on the upper-left side. Settings were on the upper-left. There was a dock at the bottom for most-used applications and an app drawer to hold the rest sorted into tabs.
CMD+Space to search your system was "Just Type" from the "home screen". Their unified notification feed is something I haven't really seen iOS or Android even attempt.
I once heard the iOS app paradigm was the equivalent of having a house with only doors facing to the outside. Going from your master bedroom to the master bath requires leaving the bedroom entirely, walking around the outside until you find the master bath and then going in.
When you multitask on OSX, do you switch applications by minimizing your app and opening it again from a desktop icon or from the app drawer? Nope. You use expose/mission control to see what's open on your current screen. You can also swipe left/right to view other virtual desktops. Your running applications (rather than your desktop) is your default view.
Same thing with webOS. Swipe up for expose where you'd see your current fanned out set of cards (one per app). Swiping left/right would show different sets of cards that you could create/rearrange based on whatever task. Just like OSX, those tabs would be LIVE rather than paused background stuff.
The default view with webOS was also application-first rather than desktop first. iOS and Android encourage having EVERYTHING "open" even though anything past the last handful of apps will probably have to reload anyway. The result is that finding anything useful in that deck of cards is very hard. webOS encouraged sorting that list and keeping it limited to what you were actually using.
While all the differences may seem small, but together, the overall experience feels much different.
HP's second (third?) CEO of the year killed the whole palm division when an investment and licensing webOS could have made HP/webOS into what Google/Android is today. They were finally coming out with decent hardware designs with bigger screens and without the dedicated keyboard.
Their in-progress Mochi design would be around a decade old today, but when you look at it, it has an aesthetic that I think most people would find very refreshing today.
To think that HP was once a well respected company making quality products (test equipment, ICs, medical devices etc.) & known for good management ("HP Way").
All flushed down the toilet in a span of ~10 years in the 00s, now known as a purveyor of subpar laptops and printers.
A shame that the HP brand didn't stay with what turned in to Agilent and Keysight.
In design, they paid a lot of attention to making common actions available with your free thumb so you could navigate most apps with one hand. App-switching, context menus, device operations were all swipe operations.
Having a hardware keyboard made it a bit chunky but didn't feel bad in your pocket because it was so smooth. Also the hardware keyboard provided a true tactile feel so you could even type out some messages without looking at your screen nearly as much as you need to with on-screen keyboards.
