What does Grey Hat SEO mean?
The way people carry out search engine optimisation is categorised in three ways - White Hat, Grey Hat and Black Hat.
is seen as an "honest" approach which aims to make the job of search engine robots easier through better coding on-site and various link building methods off-site.
is seen as the "dishonest" approach which seeks to mislead search engine robots. This could be trying to present a website as being about one topic when it is in fact about another or spamming forums to build links.
But because "honest" and "dishonest" are hard to define and agree on a third category, Grey Hat, is used. These are optimisation practices that some might consider misleading while others say they are fair to use.
Note that what is White, Grey and Black is constantly changing because search engine algorithms are changing. In general terms Grey Hat tends to move into Black Hat as search engines learn how to spot it.
For a detailed view of differences see out pages on White Hat, Grey Hat and Black Hat SEO