Mobile Also Continues Growth

Nielsen is reporting that as of last month, 48( of American adults owned smartphones.  Younger adults were most likely to own the devices (two-thirds of 24-34 age group, and 62% of 18-24 year olds).  Nielsen's numbers also show an income effect at work.

And for a related "WOW!!" statistic, Apple reported global sales of 156 million iOS devices (iPads, iPhones, and iPod Touches) in 2011 - which happens to be more than all of the Macs sold over the last 28 years (122 million).  And the pace is continuing, with Apple reporting sales of 37 million additional iPhones in the first quarter of 2012 - although  Apple was a bit disappointed.  Apple CEO Tim Cook was reported as commenting:

Yes, 37 million is a big number. It was a decent quarter... (Still, in terms of the smartphone market) there's three out of four people that bought something else. And it represented less than 9% of the handset market, so 9 out of 10 people are buying something else... up against (that), the numbers don't seem so large anymore.

So I guess there's still room for further growth

Sources -  Nielsen: Smartphone Penetration Reaches 48%,  OnlineMediaDaily
Survey: New U.S. Smartphone Growth by Age and Income,  NielsenWire
Apple iOS Devices Sold in 2011 Outnumber All Macs Ever Sold,  CIO Insight