- eMarketer Staff

The ready availability of mobile phones, the growth in ownership of smartphones and the introduction of advanced features on various mobile devices means that media consumption -- and, by extension, advertising exposure -- is happening anywhere, anytime. And it's becoming especially prevalent among kids and teens.

According to the Kaiser Family Foundation, 66 percent of children ages 8 to 18 owned a mobile phone in 2009, up from 39 percent in 2004.

There was a noticeable spike in the 11-14 age group. According to Kaiser, ownership increased from 36 percent in '04 to 69 percent last year -- nearly doubling in just five years.

"The child and teen mobile audience is growing rapidly and there will be many opportunities to market to them," said Debra Aho Williamson, eMarketer senior analyst and author of the report "Kids and Teens: Mobile Everywhere."

She added: "Today, a mobile youth marketing strategy must focus on feature phones, because many young people own them. But the smartphone user base will grow quickly, and so marketers must explore ways to participate in mobile applications and app advertising via smartphones."