Cisco came up with an interesting prediction in its latest forecast of global mobile data traffic: by the end of this year, there will be more Internet-connected mobile devices than people on Earth.

"By the end of 2012, the number of mobile-connected devices will exceed the number of people on Earth, and by 2016 there will be 1.4 mobile devices per capita," Cisco said in its Global Mobile Data Traffic Forecast Update released today. "There will be over 10 billion mobile-connected devices in 2016... exceeding the world's population at that time (7.3 billion)."

The numbers include not just phones but tablets, laptops, handheld gaming consoles, e-readers, in-car entertainment systems, digital photo frames, cameras, and "machine-to-machine modules." That latter category includes applications such as using wireless networks to update digital billboards.

Global mobile data traffic doubled for the fourth year in a row in 2011, and will grow 18-fold by 2016, hitting 130 exabytes a year (the equivalent of 33 billion DVDs, 4.3 quadrillion MP3 files, or 813 quadrillion text messages), Cisco said. Not surprisingly, streaming content, video in particular, is expected to play a huge role in increasing data traffic. Good news for users: mobile network speeds will increase nine-fold by 2016. Bad news: the days of unlimited data plans seem to be expiring quickly, with few exceptions.