The following graph shows the Monthly Active Users for Facebook since mid 2011. The emerging dominance of the mobile venue is abundantly clear.
If the 1.2 billion monthly Facebook usage is not a bellwether I am not sure what is. You decide.
Since the first quarter of 2012 a new category of 'Mobile only' has emerged. This category's increasing popularity is an indication of eventual total domination of mobile platform in computing usage patterns.
Enterprises with a lagging comprehensive mobility strategy are doing so at their own peril. This is not just a conjecture. There is an over-abundance of empirical evidence that supports this assertion.