What do two-thirds of all Americans over the age of 17 have in common?

We visited Google.com in the last month. Furthermore, nearly half of us will visit the site today. Both figures are from Media Audit’s latest national report.

We use Google and other search engines such as Yahoo, MSN and Bing to find answers to all sorts of questions, and we increasingly access search engines not just from our desktop computers, but also from mobile devices.

We are also using computers and mobile devices to stay connected or be entertained through social media. Our daily interaction with sites such as Facebook, LinkedIn or YouTube has become a fact of life. In fact, 34 percent of females reported that using social media was their favorite leisure activity.

So, you no longer can question the size of the audience and the power of online media. As marketers prepare for the post-recession economy, they are almost universal in their plans to increase online spending, especially in social and mobile media.

Strong Mail, a California online marketing firm, surveyed 1,000 businesses globally and found that 59 percent plan to increase spending in social media and that 22 percent expect to boost their investment in mobile marketing.

“No longer will social media be considered a curiosity, but be seen as an aligned channel designed to integrate with other, more traditional, forms of marketing. The end result will be that more money will be shifted to online and, specifically, social media,” said Paul Chaney, author of The Digital Handshake, in a year-end piece in SmartBrief for Social Media.

Digital publisher eMarketer projects mobile ad spending will rise from $416 million in 2009 to $593 million in 2010 as more brands and agencies integrate mobile into their marketing mix.

“Whereas consumers once limited their mobile phone purchases to downloadable ring tones and games, today they’re using their devices to buy books, apparel and other items associated with online shopping on a PC,” said Jeffrey Grau, eMarketer senior analyst.

What do these trends mean for marketers? Shiv Singh, vice president of Razorfish, a leading New York digital agency, declares these points to be guiding principals:

• Brands must become more social. Owners and marketers must let employees and customers be their brands’ face and voice.

• Brands must work in real time. Owners and marketers must commit to operating dynamic brands that respond to feedback, and they must be willing to react quickly to changes in the market.

• Brands must manage customer relationships. Owners and marketers must focus on understanding their customers and acknowledge the influence that customers have — individually and in groups — on brand success.

Marketers cannot rest on their laurels. Times have changed.

Commentary by David Bohan