Most things in this world have shades of grey; few things are purely black or white. This holds true for SEO techniques also. While we have discussed the right and wrong, the white hat and black hat techniques, this study will not be complete without donning the grey hat. Mind it, this is not the middle path, but the lesser wrong, which might not always be caught and penalized; nevertheless, it must be avoided.
Links are always tricky for SEO professionals. Earlier there used to be reciprocal links; but that was before the Panda update. Unnatural links have made an exit, making way for the grey hat technique of three-way link exchange. This is where a series of links are created, joining one to another. Spinning is a common terminology in marketing and advertising circles. When it comes to SEO, article spinning is a technique followed by many article marketers. Suppose you find an amazing article, which contains innovation, information and a hint of promotion; you think that it would make great content for your campaign. You make slight changes here and there, add some lines and publish it as original. This is considered a part of grey hat SEO. In fact, this can demean to black hat SEO if the article which has inspired you, is not original in the first place.
Another technique is buying old domains, which have high ranking back links and placing the sites which you want to promote on the domain. People may also buy domains which have expired and use them for placing the web pages which they want to promote. However, Google is smarter and resets the links on the domains which have expired. The last technique we will talk about is Google bombing. This is the process by which a website is promoted on the basis of non-relevant keywords, or content which is not related to the topic of the website. Keywords, which are high ranking or searched often, are used for this technique.
If you adopt grey techniques, you might not be in the risk zone, but you must be careful, and ready to be caught unawares.