Cue the music from a spaghetti western … it’s the black hats versus the white hats.
Basically you have the good guys versus the bad guys. The white hats play by the rules and don’t do anything considered “evil”. Although evil in the Internet/SEO world isn’t quite what it was in the Old West.
So what constitutes good and bad in the SEO world? Actually it’s really hard to tell sometimes and there’s a whole lot of grey in between. But there are people who go out of their way to avoid the nasty, spammy stuff.
That’s really the best way to label the Black Hat SEOs – spammy. There are lots of things they do, but in a word that’s what they are. They do things like comment form spam, social profile spam, article spinning, link wheels and getting mass links from content farms. There are automated ways to do most of this and they’ll just hammer sites with their programs generating backlinks to their sites. In some cases they’ll do things manually, but that takes a lot of time.
The White Hats think this is evil, or at least they don’t want to risk their sites getting penalized to taking the risk of doing these sorts of things.
The “lawful good” White Hats think that what they’re doing is hurting the Internet by creating all the garbage that the search engines have to sort through. It makes the Internet a worse place for everyone because the relevant, good content is harder to find.
The “chaotic good” White Hat SEOs just think that they can do SEO without taking the risks that Black Hats do. For instance, if Google finds out that a site is doing Black Hat methods to game the system, they can be eliminated from the rankings entirely or at least punished with a downgrade in where they’ll show in the SERPs (Search Engine Results Pages).
In either case, both White Hat SEO camps believe that great content, a well-built site optimized for the desired keywords, and quality inbound links will generate good SEO results – without spam and without risk.
There are those who play on the fringe. No one knows exactly what Google’s algorithm is or exactly what they’ll penalize for. These Grey Hats will optimize the site, create good content, and perhaps play with some nefarious, questionable linkbuilding.
What should *you* do? Well no one can can say but yourself. However, if you’re doing a site for a client, you usually can’t take the risk of getting them banned from the search engines. You should probably stick to 100% White Hat SEO techniques unless you make the client aware beforehand and come to an agreement about their SEO campaign.