I've had some experience in SEO and have had the pleasure of seeing some projects rise. I'm curious to know if anyone here has had any experience on the downfall? Is it possible that a competitor can destroy your rankings? If so then how would you know? I know this is a broad question, however, I'm wondering what happened to a specific site that I had that recently dropped significantly in ranking. There's really no other logical conclusion rather then the negative influence of a third party. The biggest question would be how to determine what was done and even more so - can the damage be repaired?