Search engine deoptimization is a niche industry that exists to fight bad press for those clients who suffer from it. Why on earth would someone want to hide news about them from a search engine? Well, if a CEO gets arrested, your product gets unreasonably bad reviews from unknowledgeable bloggers, etc. Internet defamation can be stopped by hiring a search engine deoptimization firm that knows what they’re doing.
http://www.isedb.com/db/articles/1486/1/Solid-SEO-Through-De-Optimization/Page1.html