How much data does the Internet contain?

Estimating the data the Internet contains is complicated because:

1. The Internet is not a single computer or a single network, but a network of networks, whose size is constantly changing

2. Not all data stored on these networks are necessarily accessible to all users. However, there are a few estimates. According to one, the quantity is approximately equal to 5 trillion or 500 crore pages. Another assesses the total amount of digital data in the world by 2010 would amount to 12 piles of pages, each of which would be twice as long as the distance between the Sun and Pluto. From the second one, the estimate related to data on the Internet has to be obtained by adjusting the estimate by an appropriate proportion.