Is the iPad a mobile device?

The 7" Android Tablet from Viewsonic

...and what I mean by that is, Is the iPad a mobile device or simply a portable computer; a laptop without a keyboard?

A while back, the term 'Third Screen' started to be used by marketers to describe the next platform for reaching customers. The first being the Television, second the computer monitor, and now the tiny screen in our pockets. The mobile phone.

But as we've seen, this

 isn't tiny anymore.  What was once a small, monochromatic LCD, barely capable of showing icons for menus, has evolved into arguably the best mobile screen out there today, the retina display on the iPhone4 with immense clarity, colour and resolution.  Still small though, relative to a laptop and a TV.

Well-- what about netbooks?  They're the second screen, but their sometime ~6" screen is tiny.

Which brings us back to the ipad-- and frankly any tablet.  Tablets are, by definition, larger than phones, and they have the computing power similar to or greater than netbooks, along with things like multiple cameras (Blackberry Playbook) or touch-screens (kind of necessary when there's no keyboard.)  Do these still count as mobile devices, since they have a 3G connection and you carry them around, or should be think of them as laptops without keyboards?

Let's look at the development of content for a moment.  When you need to design a

 website, what does that mean?  It means you strip out design and function, and put back mobile-necessary function with mobile-friendly design.  The content may be the same, but design and function change. (I'm over-simplifying a little here).

So what about when you want to optimize for mobile devices--how do you make your site look great and function properly on a tablet.  You know people could be walking down the street with it (even though only about 10% of ipads leave the house) but you've got a screen that from a design perspective could show all your content in its original layout. It's not a phone. --but it's not a regular computer either.  If someone needs to enter info on your site from a tablet, the tablet is going to pop an on-screen keyboard-- how's that going to look over your site?

Now, where do we draw the line.  Here's a list of screen resolutions by manufacturer.

On a tablet that's 5" should we show the mobile version or the full version of the site?  Should there be a

 third screen?  Let me know what you think?