Let's look at a definition of symbiotic relationship:
A symbiotic relationship is a relationship between two entities which is mutually beneficial for the participants of the relationship. Thus there is a positive-sum gain from cooperation.
That's a great definition. Here is a great example of symbiotic relationship featuring Al Sharpton and Fox News:
“Check out this,” the flamboyant civil rights leader told me during breakfast at his organization’s annual meeting this week. He flipped through the program until he found a full-page ad with the logos of Fox News, the New York Post and the Wall Street Journal. “News Corporation Proudly Supports National Action Network’s 2012 Convention,” it said.
Sharpton grinned. “They bash me on Fox News,” he said. “But they sponsor my conference.”
Do I really have to say anything else about this?