A lawsuit for "civil conspiracy and fraud" has been filed against an SEO organization called The Rainmaker Institute. The SEO firm reportedly used practices and techniques that were in violation of Google's guidelines and knew that the practices were not going to achieve their advertised results (and would actually have the opposite effect), planned to use automated programs (instead of direct personal effort), and wrapped it all up in secrecy in the name of "trade secrets".
Would you believe me if I told you that I have seen evidence of the potential for this type of behavior in a few of the SEO companies that have approached our clients? Obviously I advised our clients to look into the companies further and ask more questions before signing a contract.
I strongly recommend you only work with an SEO company who is willing to provide 100% transparency into their practices and to explain what each of their strategies means, rather than just throwing a bunch of techno-mumbo-jumbo at you.
You can read more about what you should be looking for in an SEO company in my article Picking the Right SEO Vendor.