Signal to Noise

From Johannes, the world generated 161 exabytes of info last year.

I wonder how much of that total consists of

1. blog posts examining the criteria for 'user-centric' identity?
   
2. duplicated account profiles from repeated user form-fill?
   
3. redundant content from misuse of blog copy-and-pasting?
   
4. MySpace profiles of girls named Tiffany?