I think Gooner is thinking of Spamdexing. I put a page together about this, it’s outdated now but still has the basics:
http://www.gamesandcasino.com/blackhat/black-hat-seo.htm
You will find a series of more specific articles if you scroll down on this page: http://www.gamesandcasino.com/affiliate/articles.htm
Blackhat is a huge area, and the line between blackhat and white hat is somewhat blurred.
At its very worst it includes hacking into other people’s sites and adding/changing stuff that will boost the blackhatters profits one way or another.
It also includes methods to drop a competing site from the serps.
The grey area is attempting to manipulate the search engine’s view of one’s own site.
Theoretically, everything not in the google guidelines is black hat.
That includes some things that many people do:
Quality guidelines – specific guidelines
Avoid hidden text or hidden links.
Don’t use cloaking or sneaky redirects.
Don’t send automated queries to Google.
Don’t load pages with irrelevant keywords.
Don’t create multiple pages, subdomains, or domains with substantially duplicate content.
Don’t create pages that install viruses, trojans, or other badware.
Avoid “doorway” pages created just for search engines, or other “cookie cutter” approaches such as affiliate programs with little or no original content.
If your site participates in an affiliate program, make sure that your site adds value. Provide unique and relevant content that gives users a reason to visit your site first.
The thing webmasters most commonly complain about is spamdexing. It involves using software to create (literally) tens of thousands of sites. These sites often capitalize on the work of others, scraping, URL hijacking and all sorts of tricks. It’s a vast category on it’s own.
I draw distinct lines in the way I look at it.
If it is something you do to your own sites without using the work of others in any way, in my own view (you can argue the point til doomsday but this is where I draw the line) it’s not blackhat. It’s trying to manipulate the engine’s view of your own site with methods that do not capitalize on the work of others. This is usually called grey.
As soon as it involves using the work of others without permission, in any way, shape or form, I call it Black Hat.
A site that completely conforms to google’s guidelines at all times is completely white hat.
One needs to agree at least on some definition, otherwise any discussion of the matter is impossible.
Blackhatters tend to like to blur the line to justify their own actions by saying that we all do the same. We definitely do NOT all do the same.