As tablet computers proliferate and look more and more alike, Apple and Samsung have thrown down the legal gauntlet.

A California jury Friday found Samsung infringed Apple smartphone patents, hours after a South Korean court ruled each company infringed the other's patents.

The jury in San Jose awarded Apple more than $1 billion in damages after concluding Samsung infringed a series of Apple patents on smartphones and tablet computers. While the jury rejected Apple's claim that Samsung's Galaxy Tab 10.1 tablet infringed on physical iPad design patents, the decision could bring about significant changes in the smartphone and tablet industry, Wired said.

Whatever the outcome, it is undeniable that the form-factors of tablets from different makers -- including Samsung -- are very similar, and one of the few things a differentiating consumer is left to consider when eyeing a purchase is "real estate" as expressed in screen size.

Apple has set the standard with a 10-inch screen, and the majority of tablets now being offered fall into that size category.

The late Steve Jobs thought 10 inches -- well, the iPad is technically 9.7 inches -- the perfect size compromise between usability and portability, and what Steve Jobs thought tended to end up enshrined in the hardware.

Ten inches is a good size for displaying content without excessive scrolling or zooming, and can offer an on-screen keyboard of sufficient size for comparatively easy typing.

But although a good fit in a backpack or briefcase, a 10-inch tablet can be a bit of a stretch for a woman's purse and certainly for any pants pocket.

Enter the 7-inch tablets, like the Amazon Kindle Fire and the Samsung Galaxy Tab.

A pause here for a brief bit of geometry. While 7 inches doesn't sound that much smaller than 10, the screen area of a 7-inch tablet is in truth about half that of a 10-inch.

Why? Because advertised screen size is a diagonal measurement, whereas a true height times width measurement to produce screen size in square inches shows that every "diagonal" inch smaller means a considerable reduction in actual screen area.

In simple numbers, a 7-inch screen like the Google Nexus 7 is about 22 square inches, while an iPad or other 10-inch tablet is sporting about 45 square inches.

Not to say smaller doesn't have advantages, chief among them being 7-inch tablets are usually lighter and thus easier to hold, and being about the same size as a paperback book, they are a perfect platform for e-books.

They'll fit nicely into a woman's purse, and can even -- at a stretch -- fit a large pocket in a pair of jeans or cargo pants.

Going smaller than 7 inches raises the question of when is a tablet a tablet, and when does it become a smartphone.

The latest wave of smartphones includes several whose screen size has reached, and even slightly exceeded, 4 inches, and some tablet makers, like Dell, Acer and Archos, have moved -- downward -- to meet them with screens of about 5 inches.

However, any tablet-like advantages quickly disappear at that size, leaving a Web browsing experience that can be matched by almost any large smartphone.

The small size also means smaller batteries, with the same longevity limitations with which most high-end smartphones struggle.

So, then, does size matter?

In the end, and despite which way lawsuits go, every size is likely to find a happy consumer, based on what a tablet can do for them combined with what they have to do with the tablet in terms of incorporating it into their lifestyles -- or into their backpack, purse or pocket.