Global access capacity gap
A 2007 Nemertes Research report predicts that by 2012 Internet access network capacity (though not backbone capacity) will fall short of demand due to increased use of portable and mobile devices and video content. This illustration, taken from that report, (free for download) shows backbone fiber and backbone and access switching capacity are sufficient, but capacity falls short in access networks.
This does not mean the Internet will break, but we will have slow access -- a diminished user experience. That in turn will cut demand for new services and innovation will slow.