The huge amount of data being seen and sent means that for the first time the annual total of data travelling over the net will exceed one zettabyte, according to Cisco.
"Today, we are firmly in the zettabyte era and witnessing incredible innovations and shifts in the industry," said Doug Webster, a spokesman for Cisco, in a statement.
By 2018, more than half of all the data would go to mobile devices connected wirelessly, said Cisco. At the end of 2013 about 56% of data travelled through fixed connections but this would drop to 39% by 2018 with the rest going to mobile gadgets such as smartphones and tablets.
Increasing mobility, greater use of ultra-high-definition video, and the rise of the "internet of things" would all contribute to rising data volumes, it added.