Almost one-third of U.S. mobile customers now own a smartphone, according to a December 2010 report by the Nielson Company. The report also revealed that smartphones are particularly popular among specific demographics that tend to skew toward younger populations—for example, 45% of U.S. Hispanic mobile users have moved to smartphones. (Check out the full article from Christina Warren at Mashable.)

How are your customers using smartphones?

Chances are they’re accessing social networks. According to another Mashable piece, a TNS study found that mobile users spend 3.1 hours per week using social networks on their devices, more than the 2.2 hours they spend per week on email. The same study showed that U.S. consumers also expect to increase the amount of time they spend accessing social media via mobile.

What does that mean for brands?

With the rise in smartphone use, consumers have increasing access to social network sites on-demand. Stumped by choices while car shopping? Buyers can check out expert reviews while standing in the dealership lobby. Did the special at the local restaurant taste like discount cardboard? Diners can spread the word before they even leave the parking lot.

As if brands needed one more reason to develop a total social media strategy…

Consumers have the power to share and research information while on-the-go. They’ll read reviews, do research, and ask questions. Brands that aren’t monitoring social media or providing real-time online customer engagement will lose out to companies that do.