Is there any way to estimate how much data is added to the world wide web each second? Are there any studies about this?
There is much interesting research in this area that is ongoing. See eg
Using search engines to estimate size based on pages counted eg How Large is the WWW by Dobra and Fienberg
Theoretical models of networks that model the growth of the web and reflect its small world graph structure eg Models for the Growth of the Web by Ho, Pu, Tsiatas