Call it the “year of the smartphone.”  Smartphone growth in 2011 “could totally eclipse anything we’ve seen before,” says Seth Weintraub at CNN’s Fortune Tech. And that includes traditional computer sales. A study by Deloitte Canada predicts 425 million smartphones and tablets will ship globally compared to 400 million PCs. Just imagine what that ratio will look like in 2015.

So what’s driving this unprecedented growth? Improved wireless infrastructure across the board and cheaper hardware, which eliminates the need for subsidies and improves competition between carriers. Google Android head Andy Rubin calls this a ‘perfect storm’ for smartphone adoption. He’s right.

And the smartphone revolution won’t just take place in the most prosperous countries. Drastic price cuts will bring smartphones to developing countries as well, where current costs often restrict smartphone access to the elite. In 2010, the cheapest smartphone cost about $200 (with some Chinese brands as low as $150). According to CNN, that figure could soon be cut in half. If that happens, very little would prohibit the most basic Internet user from using a smartphone in lieu of a PC.

According to a September IDC report, quarterly shipments of Android phones had hit 10.1 million units by June 2010, outpacing the Apple iPhone at 8.4 million and closing in fast on second place BlackBerry (11.2 million).

Meanwhile, iPad sales skyrocketed, netting Apple $4.6 billion in revenue so far and trumping past forecasts — by a longshot. And don’t underestimate social media’s role in the smartphone craze. With the advent of Foursquare, Yelp, Groupon, and Facebook Places, location-based marketing promises to attract more and more companies hoping to capitalize on the powers of local commerce.

How will this all play out? TechCrunch highlights the “ultimate product” for a mobile app: a user launches an app, sees deals in her area, which friends have already purchased various products, reviews of each product, and the option to purchase with a single click. She could then walk into a local business, code in hand, and redeem what she had just purchased. What savvy shopper wouldn’t love that?

Without a doubt, we’re about to go app-crazy. Mobile App downloads are forecast to top 4 billion this year and grow to 21 billion by 2013.  It’s a win-win for consumers and businesses, which can track what’s working for their customers—and what isn’t.  “The next, great scalable opportunity and challenge is mobile, which in the end will translate into local advertising revenue,” says new media critic Jeff Jarvis. “Mobile will give Google (or Facebook or Groupon or Twitter or Foursquare … we shall see) the signals needed to target content, services, search, and advertising with greater relevance, efficiency, and value than ever.”

To put all of this another way, if your business or brand is not thinking about smartphone technology — and thinking about both the Andriod and iPhone operating systems — there is no time to lose. This is the year of the smartphone. Be ready for the call.