Google maintains a supplemental index (known as Google Hell in web marketing circles) for sites that are considered spam, invalid, too out of date, etc. Being in the supplemental index means that your results won’t show in the first few pages of Google search results. For businesses relying on search engines to drive traffic to their sites, this can have the practical effect of closing shop for a few days a week. There is a lot of lost profit from the reduction in organic search results.

The key for web marketers is to be very careful how you market your site. Using a company that relies on ubiquitous linking strategy could be the death nail that kills your profits. Be very careful and monitor your site stats aggressively.