What is negative SEO?

[bcetindra]

 Negative SEO is basically the exact opposite of search engine optimization. Meaning the intent is to drive search rankings into the toilet instead of increasing search visibility in Google.

[yashepe]

Negative SEO means "short term happyness".. By doing negative things, what you think how long you will survive?

The only thing that will let you through is your hardwork and smart work.. Just build slow and steady, else search engines are ready for putting penalties.

thanks

[lucygomez]

Negative SEO can refer website hаcking. From removing content or even deleting your site entirely, to changing the robots.txt file to tell search engines to stop crawling it. It can also be about damaging your reputation, perhaps through fake social media accounts set up to specifically badmouth your company.

[Emmaballet20]

Very interesting! How much effort do you think it would take to execute a negative SEO campaign like this? One would have to have a spider/crawler, or slumberous spiders/crawlers, and then there's the bot.

[James10]

Negative SEO means unethical SEO in another word you can call it black hat SEO. Black hat SEO is against about Google rule and regulations. Black hat SEO is the techniques that are used as to get high ranking in a search engine result page. Below I have mentioned some black hat SEO, so please take care of all these things.
Cloaking
Doorway pages
Keywords stuffing
Duplicate content
Hidden text 
 

[Talukdar]

Negative SEO refers to the practice of using black hat and unethical techniques to sabotage a competitor's rankings in search engines. Negative SEO attacks can take a number of different forms: hаcking your website. Building hundreds or thousands of spammy links to your website.

[sagabizsolutions]

Negative SEO on a website can take many varieties and cause various levels of damage
 Negative search engine optimization includes
Buying hyperlinks and pointing them to a competitor’s web page to be able to negatively affect their search engine rankings.
Website hаcking to have an impact on a web site’s natural seo techniques.
Reporting a competitors black hat search engine optimization efforts.

[Emmaballet20]

It would be really scary if this was true. I'm surprised that with all of the other ranking factors in the algo that this would have that much weight since it apparently is so easy to influence by one person.

[TomClarke]

Negative SEO occurs when someone makes attempt to lower a site's rankings in the search engines. There are multiple ways that this can be attempted. The most common type of negative SEO that gets discussed is link based negative SEO, but there are many other techniques that unscrupulous people can use to try to reduce your rankings.
Negative SEO on a website can take many forms and cause varying degrees of damage, when applied to a competitors website. Negative SEO methods are used to convince search engines that they should punish  a site for using Black Hat SEO techniques when they have not. Perpetrators found to be employing these risky Negative SEO methods would potentially be black listed by Google, not to mention pursued legally for loses.

[jasonhalle]

Negative SEO refer to use of black hat strategy or technique to the rank website on keywords which are highly competitive. Black hat techniques are not entertained by the search engine result page which results in the penalty.

Few black hat techniques are

1. Doorway pages
2. Hidden text
3. Cloaking
4. Article Spinning

Thanks