Black Friday could produce a milestone, this time in the PC market. If NPD DisplaySearch is correct, today, the super-shopping bonanza after Thanksgiving, will be the day that tablets outsell laptops in North America.

The rest of the world’s economies are expected to follow in 2015, when nearly 276 million tablets will ship, compared to 270 million laptops, according to DisplaySearch.

In North America, the inflection point will be this quarter when tablet shipments are expected to reach 21.5 million units, nearly 50% higher than laptop sales.

What’s Causing The Shift?

The “why?” behind the tablet juggernaut lies in the U.S., where more than 70% of households have PCs. With such a high penetration rate, pretty much everyone who wants a PC has one and the majority is choosing to buy a tablet rather than upgrade, DisplaySearch analyst Richard Shim said.

Driving that choice is convenience. Tablets are more portable than a laptop, turn on immediately and meet the basic computing needs of email, browsing and entertainment. As a result, U.S. 2011 sales soared 200%, year to year, to more than 38 million units, according to DisplaySearch, This year, shipments are projected to rise 46%, to 56 million units.

At the same time, U.S. laptop sales have slowed dramatically. In 2011, shipments fell 2%, to nearly 55 million units, and are projected to rise by only 2%, to 56 million units, this year, DisplaySearch says. (Worldwide, the PC market is expected to shrink 1.2%, marking the first decline since 2001, according to IHS iSuppli.)

Who’s Buying?

Interestingly, this is happening even as a key demographic group demonstrates ambivalence about portable computing.

People in their 20s and 30s who own both a tablet and laptop say their laptop is the more important tool of the two, according to a survey released this summer by consulting firm Deloitte. Older adults were much more likely to choose a tablet.

Major tablet vendors, such as Amazon, Google and Apple, certainly deserve credit for stimulating consumer interest. The companies have delivered solid products and have marketed them well.

Falling prices are also driving the market.

“The $199 price point has increasingly become the target to match or beat with the introductions of Google’s $199 Nexus 7 and Amazon’s Kindle Fire 7,” Shim wrote in a blog post.

While prices fall, vendors are releasing more options. In 2011, Apple’s 9.7-inch iPad dominated with a 65% market share, Shim said. This holiday season, companies are trying tablet sizes between seven and 10.6 inches.

The Fate Of The Laptop

Laptops won’t be going away anytime soon. While tablets are convenient for simple chores, content creation still demands and a higher-performing system. From 2013 to 2016, laptop shipments worldwide will have a compounded annual growth rate of roughly 7%, according to IDC.

Laptop growth in emerging markets will be much higher than in mature markets like the U.S., Western Europe and Japan, where the majority of people own a PC. Companies looking for growth rates over 10% will have to target Asia/Pacific, Latin America, Central and Eastern Europe, the Middle East and Africa.

Everywhere else, people will be holding on to their PCs much longer and will need to be given a good reason to upgrade.

On the tablet side, recent history shows us that even in a nightmarishly uncertain economy, people don’t need a good reason to upgrade or even buy. Many hardly need a nudge at all. All hail the new tech king.