I can see a use for WebOS:
The quick to start OS on a laptop so you don't have to wait for Windows to read War & Peace
before you can surf, read emails, etc. (more suited to the PC division)
The main OS on a netbook. Linux didn't go down that well on netbooks because it wasn't windows that people knew. However now that smartphones / tablets have iOS and Android that are not windows, and now that more is being done using cloud apps, maybe, just maybe it can work. (more suited to the PC division)
Alternative for a lights-out processor. Only needs a puny ARM processor, but can still do quite a lot. (more suited to the PC division).
WebOS in a HP that just sells software services that normally run on big iron or racks of servers? I must admit I'm a bit lost.