Negative SEO is usually pursued by competitors, in order to increase their own rankings, by strategically lowering the rankings of their more popular competitors. Well, being the top ranking website in your niche typically means greater traffic which usually translates into bigger sales and profits. Some websites have even begun their own business where they offer negative SEO services. :)
like animita was saying ... it's a dirty SEO trick, definitely a black hat search engine optimization technique. It mostly involves acquiring links to your competitor webpages from bad neighbourhoods in an effort to demotes your competitor's value. Bad places to acquire links include, link farms, penalized web pages, free-for-all links, using link brokering services in a detectable fashion, dumpster directories, obvious blog comment spamming etc..
I think of negative SEO is same as black hat SEO. making links, stuffing keywords into site that the veiwer can not see and many more things, but the negative point of that is you may be banned by Google for doing that.
Negative SEO is reverse of SEO.
The purpose of negative SEO is to down the ranking , traffic , popularity etc of a website .
In Negative SEO the activities are as suspect reviews, spammy backlinks, wesite hacks and more.
Usually negative SEO is done by the competatior to drop the keyword ranking. So you should have to aware with your link profile, if you found any negtige links in your profile, than go to webmaster tool and remove these links form your profile.
Negative SEO is essentially when a competitor points bad links toward a website in order to make their own website look better or to decrease the competitors keyword page rank.The following are the tacttics of negative seo-
1. Bad back links- competitor may go to spam sites and put back links to your site.
2. Report you as spam