The decline of paper (for real this time)?
WSJ has a short little snippet about how paper consumption is not increasing as fast as previously with increasing GDP.
Dating back to 1994, the correlation between quarterly growth in U.S. paper shipments and U.S. GDP has ranged between 0.58 and 0.93, with 1.0 indicating perfect correlation. Today, it stands at 0.32. Intriguingly, though, Ms. Huberty points out that the divergence between paper shipments and GDP growth began around the time the first iPad was introduced.
The WSJ has this as a warning for printer companies (e.g. HP, Lexmark). I think there are other companies (Staples, Office Depot etc.) that should be worried too unless they are diversifying their products/services.