Social Media and Advertising - Getting Bang for Your Buck?

Increasingly firms are using social media to promote their brand, perceiving it as a more cost-effective way to generate brand awareness. But are these firms getting bang for their buck? http://www.ft.com/intl/cms/s/0/2c6bf3e4-4d87-11e1-b96c-00144feabdc0.html?ftcamp=rss