According to
www.internetworldstats.com/stats.htm about 1.4bn people of the earth's 6.6bn population have access to the internet at this time.
That means 5.2 billion do not.

Right now, someone somewhere is going online for the first time.
On its homepage, it points out that
Asia has a marked increase in internet users. Some 578m people now surf the web there, apparantly.
It also highlights the fact
China now has the largest number of internet users in the world, 253 million of them and counting...
And with the mobile internet catching up it's fixed-line brother fast, it is safe to assume that more and more of these people will be accessing your sites from their mobile devices.
It's a big world out there, go get busy
