a term used to describe a hacker who has the intention of causing damage or stealing information

A malicious hacker who exploits - or publicises - a security weakness before informing the affected organisation.

SEO methods which will get a site banned from most search engines.

A person engaged in or tactic used to increase search engine rankings using methods frowned upon by search engine companies.

Unethical use of seo techniques.

See SEO Explained for a more in-depth explanation. Practices used that fall outside the "Search Engine Guidelines". Are seen as risky methods for boosting search engine ranks and gaining traffic.

A malicious or criminal hacker, who uses their skills and experience for personal advantage or gratification. This title also referees to crackers and when the media refers to a hacker this is what they actually mean. See also White Hat

This refers to a malicious hacker. If a hacker finds a security hole and exploits it or lets others know about it before letting the people affected by the hole know about it, then they are described as a black hat hacker. This term comes from cowboy movies where the bad guy would wear a black hat.

is used to describe a hacker (or, if you prefer, cracker) who breaks into a computer system or network with malicious intent. Unlike a white hat hacker, the black hat hacker takes advantage of the break-in, perhaps destroying files or stealing data for some future purpose. The black hat hacker may also make the exploit known to other hackers and/or the public without notifying the victim. This gives others the opportunity to exploit the vulnerability before the organization is able to secure it.

SEO'ers who use illegitimate techniques to boost their search engine rankings, like spamming, cloaking, and hidden links and text.

Pro-spam policies Grey Hat -- somewhere in between

In the context of the web "black hat" is a type of Search Engine Optimization based on spamming and/or misleading the search engines by using dishonest content and/or link structures.

A cracker. The term originates from formulaic Westerns where the bad guy always wears a black hat.

(Context: computer security) As opposed to white hat. Describes an "evil" hacker. The bad guys.

Black Hat SEO is the use of SEO techniques that fall outwith the terms and conditions of major search engines

Originally all people with a high level of skills at computing were known as hackers. Over time, the distinction between those perceived to use such skills with social responsibility and those who used them maliciously or criminally, became perceived as an important divide. Two terminologies developed: the former became known as hackers or (within the computer security industry) as white hats, and the latter as crackers or black hats.