"The industries with the highest percentage of interactions workers have the highest spread of profits per employee," says McKinsey consulting giant in a study about the impact of the social media.

In other words, you make people more effective, you make the difference.

In terms of numbers, improved communications and collaboration from social media in four major business sectors could add $900 billion to $1.3 trillion in value to the economy, according to McKinsey.

The value is through:

• Added productivity
• Improved consumer focus
• Better functioning teams

Obviously, this is particularly effective among so-called interaction workers. People like general managers, consultative sales representatives, engineers working with teams to figure out new products, health care workers figuring out patients' needs...

For others, I guess it could be a wasted productivity.