When choosing a tablet PC or smartphone, the operating system can seem like an unimportant decision. But as discrete as Apple iOS and Google Android are, the third option - HP's WebOS - is a very different proposition again. Here's a guide to WebOS, and why it just might be the mobile platform for you.

This difference is apparent from the moment you first boot up your WebOS tablet, even before you get to the immersive meshing of contacts from multiple web services and sources, the ability to print, Touchstone inductive charging, and touch-to-share.

In the clear but multistep WebOS setup process, you start by choosing the language: English (US, Canadian, UK, or Irish), French, German, or Spanish. Next, the setup drops you into Wi-Fi setup. You then agree to the HP terms of service, and set up an HP WebOS account for backup and data restoration (including apps, settings, and accounts) and HP services.

Finally, you can name your device - a handy bit of customization that's nice to see up front.

See also: HP TouchPad review

WebOS: Just Type search bar

At the heart of WebOS's approach are the Just Type search bar (present on every home screen) and the concept of "activity cards" to represent each open item.

Just Type ties into WebOS's Synergy approach to aggregating contacts, calendar items, and other personal data from multiple services. Simply by entering those accounts, you can find someone - in my tests, for example, the TouchPad loaded profile pictures, so when I searched on a friend listed only in my Facebook profile, her info came right up in a Just Type search. Just Type can search across the web, and across different services, as well. Adding services is simple: Many accounts, including Gmail and Yahoo, are preconfigured, and the menu designs are clean and straightforward.

The activity-card metaphor works well for navigating open items - be they web pages, individual e-mail messages, or apps - although newcomers may be confused about how to open cards, fan them out, and stack them. To move among cards, you simply swipe along the left-right axis. You tap a card to open it full-screen, tap and hold to select a card and drag it somewhere else, or tap and slide up to dismiss it. To move out of a card to another one, you swipe up from just beyond the bottom bezel to minimize the card and return to the home screen.

I like this arrangement - the centered design makes it easy to navigate, as well as to group together similar things from different apps (such as a map that shows a restaurant location, plus the open email message that confirms the time for the lunch meeting). You can also group together multiple Web pages on a single topic.

Some apps, such as the Facebook app, have a menu option that lets you open an additional activity card, so you can have several pages open at once. HP hasn't indicated a theoretical maximum for the number of activity cards that users can have open simultaneously.

WebOS: interface niceties

Running WebOS on the TouchPad has lots of other interface niceties built in. A quick tap in the upper-right corner reveals the settings shortcuts; this is extremely handy, and one of the best tablet-interface tweaks I've seen, rivaling those of Android 3.1. With that simple tap, a menu pops down to show the date, the percentage of battery life remaining, the brightness control, Wi-Fi, VPN, and Bluetooth connectivity, the airplane-mode setting, the rotation lock, and the audio mute.

Directly to the left of the status pop-down are notifications, which you can flick through one by one. This unique approach is especially useful for scanning inbound text messages and email.

Another design point done well is the nicely thought-out keyboard design. With a dedicated number row at the top and conveniently situated buttons for "@" and ".com," this keyboard ranks among the most usable and touch-typist-friendly I've seen.

Yet one more thing that HP and Palm got right with WebOS: printing. Using WebOS TouchPad is the first tablet to make printing directly from the device viable and simple - if you have an HP wireless printer. I tried this function out on the HP Envy 100 e-All-in-One printer, and it worked smoothly.

Even the app navigation is fairly straightforward. On the dock, five apps - Web, Mail, Calendar, Messaging, and Photos & Videos - come preconfigured, but you can put in any apps you wish. The only fixed icon there is a cleanly designed up arrow that takes you to the Launcher. In the Launcher you'll find just four tabs, for apps, downloads (meaning downloaded apps), favorites, and settings. The preinstalled apps include Maps (powered by Microsoft's Bing Maps), Contacts, YouTube, Adobe Reader, the music player, and a Memos app (which I never got working).

WebOS offers a lot to like on the TouchPad: I found both the design and the navigation to be intuitive. Being able to edit a document in Google Docs on my laptop, and then see the document appear and refresh on the tablet, was cool, for instance.