Greyhats tend to employ blackhat tactics to a lesser degree and do also employ some whitehat tactics. It’s fair to say that they do also focus on the things which just aren’t covered by search engine guidelines and rules.
Duplicate content
Duplicate content can be entirely justified. The primary reason would be something like a site of indexed articles such as a library of works. Whilst not always penalised, the site may be given less weighting than that of an equally diverse site containing 100% unique content.
Paid links
For advertising your products or services, paid links are both encouraged and entirely legitamate. The potential comes when purchasing links simply to increase the search engine ranking or other benchmark. Question the reason for you buying links, it is unlikely that you will be negatively affected so long as you are purchasing links from a reputable source with diverse and strongly rating sites. Difficulty is more likey to come about when your link is placed in a link farm environment or a site which seems far more heavily weighted toward its external links rather than it’s content.
Cloaking
As discussed in the blackhat tactics article, there are some valid reasons behind cloaking (although it must be said, there are safer ways to achieve the same results). Nowadays, it is far safer to use the same content regardless of visitor. You can elect to offer different information via internal link (such as a no css version of your site for accessibility without images).
Scraper sites
The use of scraper sites by greyhats is well documented and understood. Whilst blackhats will be looking for any content ranking high enough to use, regardless of how much sense it makes, greyhats will be focusing on readable, good content. So, whilst using automatic methods, there is still a strong focus on actually giving the site visitor what they were expecting to see and it being legible.
It is often mentioned that greyhat (grey-hat, grayhat etc) doesn’t really exist. Many whitehats consider grey to simply be a blackhat with some morals. I disagree on the basis that even those morals create a differentiation which means that greyhats should not be bundled into the same box as blackhats.
