According to Morgan Stanley, by 2014, mobile internet usage will overtake desktop internet. This means annual shipments of smartphones will exceed annual shipments of personal computers. THIS ALSO MEANS, MORE MARKETING WILL BE HAPPENING ON MOBILE DEVICES, NOT COMPUTERS ANYMORE.
Any expert will agree that your customers are no longer at their personal computers -- they are now on their smartphones. Think about this: if you want to reach them, you have to know how to do it on their smartphones and not on the computer anymore.