This may sound like data you've heard time and again (and it is): mobile phone ownership among younger people is nearing saturation. According to Pew, 75% of teens and 93% of 18-29 year-olds in the US have mobile phones.

New survey findings underscore that mobile is a critical medium (and by extension SMS because of its ubiquity) for reaching younger audiences. Here are some mobile-specific excerpts from Pew's recent millennial social media survey data:

• Among teen cell phone users, more  than a quarter (27%) say they use their cell phone to go online . . . 35% of adults report that they access the Internet using a cell phone or other handheld device.

Extrapolating from the 35% number, which is admittedly self-reported survey data, that would mean something approaching 80 million US adults are accessing the Internet on mobile phones. Nielsen's number is 68 million; our survey data from 2009 argue that 27% to 29% of mobile users are accessing the Internet on mobile handsets.

Here's demographic data regarding US "wireless" Internet access by device category and age: 

Daily teen activities, showing the primacy of SMS:  

Related (per Nielsen): "American teenagers are using 3,146 messages a month, which translates into more than 10 messages every hour of the month that they are not sleeping or in school"