[kaio]

HP with webOS :). I really loved it. But it looks like you will need a really long breath to get attention and developers on your side for any new OS.

[catwell]

I used WebOS, and I agree. I really enjoyed my Pre3. I could never bring myself to like Firefox OS.

The best now is Jolla, which I don't think has failed at all yet (I have a Jolla C, I wrote about it shortly here: https://blog.separateconcerns.com/2016-09-16-thoughts-1.html).

[prplhaz4]

LuneOS is still under active development by the webOS Ports team:

https://github.com/webos-ports

Open WebOS became LG WebOS and is still around on their TVs...

[ksec]

Web OS is now with LG.