Relying on organic traffic is risky business. After Google’s Panda and Penguin updates, many great sites got stomped into the ground.
Theories on why sites got hit abound.
Here’s a terrific article by Glenn Gabe, 6 Months with Panda: A Story of Complacency, Hard Decisions, and Recovery | Search Engine Journal, on why a site got hit by Panda (and how it recovered):
“To put it simply, the company became complacent. I noticed a big drop-off in the quality of content leading up to the Panda attack. The posts and articles were thinner and didn’t really provide the level of knowledge and thought leadership that they used to provide. “