[Air-l] How Much Information / Information Growth

Dear members of Air-l: I am trying to find some reliable resources in relation to information growth. I found, for example several blogs or news about large data repositories in the world, but the information seems misleading and the modes of evaluation unclear (eg: http://www.businessintelligencelowdown.com/2007/02/top_10_largest_.html ; http://www.sci-tech-today.com/perl/story/19162.html ) Beyond the well known Lyman and Varian 2003 study ( http://www2.sims.berkeley.edu/research/projects/how-much-info-2003/ ) does anybody knows any other recent extensive study in this area ? Thanks in advance, Jose-Carlos