B L Ochman is on the button with

I must have read and heard a hundred times that viral marketing is an inexpensive way to get a message across. Nice idea. But it's not true.

To be good in the use of social media takes time, and costs money.

Her example is about video but it applies to all new media work

The cost of creating value from the long tail is huge but can be multiplied by a factor of three with good management.