Internet World Stats is a good site for interesting and often surprising statistics about Internet access and use across the world. It includes pages on penetration rates, languages, and much more, which provide a useful background for study the digital divide and cultural diversity.
Other sites include statistics about the language of websites and device statistics which also make interesting reading.
It is easy to assume that many or most people have Internet access. However, this is far from the truth. According to a recent report in the Telegraph, more than half the world (57%) still do not have Internet access.
How Much of the World Has Regular Internet Access? is a UN report which reveals some interesting trends - including significant gaps between the percentage of women who have Internet access globally and the percentage of men. In some areas the difference is as high as 50%.
Even in more developed countries, there can still be a digital divide: the Pew Research Center claims 15% of Americans do not have Internet access - with age and lack of finance tending to be a barrier to uptake.
Of course, as with any statistics we should be careful to understand how, when, and by whom the measurements were made, as the Internet can evolve very quickly.