Mobile adoption among B2B and B2C users has exploded over the past few years, and it's only going to continue to rise: - ComScore reports that 69.5 million people in the U.S. owned smartphones during the three months ending in February 2011, up 13 percent from the preceding three-month period. - Smartphones outsold PCs for the first time ever in February, according to IDC, while 43 percent of the total mobile population in the U.S. will have a smartphone by the end of 2011. Because reading email is the number one activity on smartphones, it's only a matter of time before all of your emails will have to be mobile-friendly. Get the full story at ClickZ