webOS 3.0: Synergy
The absolute best part about webOS has nothing to do with its well-laid-out GUI. It has to do with Synergy. HP uses this term to refer to a feature in webOS that merges multiple sources of information into one interface. For example, when I register my Google and Facebook accounts, all of my scheduled events appear color coded in the Calendar app.
Facebook pictures are integrated into the Photos & Videos App. But webOS goes one step further. It's also possible to print directly to wireless HP printers.
Integration is even better when it comes to contacts and messaging. You can register multiple accounts, such as Facebook, LinkedIn, Yahoo, Skype, Microsoft Exchange, AIM, and Google. The names are automatically sorted in such a way that “John E Smith” listed in LinkedIn is tied to the “John E Smith” friend from Facebook.
If the user names from one account to the next are a little different, then you need to manually associate your contacts. Once that's done, though, the data is automatically backed up to your webOS account.