Gray Hat SEO is about risk versus reward. A large number of SEO solutions are categorized under Gray Hat SEO tools. Some Gray Hat SEO services tend to use more dubious devices and take bigger risks. While some Gray Hat techniques may largely obey search engine rules, others might land you in trouble and need serious consideration and necessary precaution before use. Gray Hat SEO techniques remain ill-defined by all Google SEO guidelines.
Grey hat SEO can also be black hat SEO and SEO advice by idiots giving advice they have not verified and tested themselves as to it's value or effect (bad or good) silver SEO can also be black hat SEO advice made feigning innocence but with a silvery tongue thta deceives and leads astray and gets you in the bad folders or next to nowhere - along with the above and the following too most likely Grey hat SEO's don't wear shiny hats and silver hat SEO's prefer theirs to shine brighter than the duller grey hats (That's a joke btw )