Is Social Media waste of employees' time??

Afraid that workplace internet leisure browsing is destroying people's ability to concentrate on real work ?New research from University of Melbourne has shown that social media increases employee productivity by 9% ..... The post on ReadWriteWeb comments that it can increase productivity a great deal more than this, if someone uses twitter, blogs etc. wisely.
As they say :Try using these social technologies for on topic work and you'll see productivity increases that make 9% look like nothing.