BLACK HAT SEO

Black hat SEO is typically considered the “BAD” kind of SEO, as it involves techniques that the search engines do not approve of. Basically, anything that goes against Google guidelines would be considered a black hat method. These are following black hat methods:
1.Hidden text – Create modern CSS based websites with JQuery effects. They often hide large portions of text in layers to display them on click or mouse over for usability reasons. Example: CSS pagination.
2.IP delivery – Offer the proper localized content to those coming from a country specific IP address. Offer the user a choice though. Shopping.com does a great job here.
3.301 redirects – Redirect outdated pages to the newer versions or your homepage. When moving to a new domain uses them of course as well.
4.Cloaking – Hide the heavy Flash animations from Google, show the text-only version optimized for accessibility and findability.
5.Paid links – Donate for charity, software developers etc. Many of them display links to those who donate.
6.Keyword stuffing – The content is stuffed full of keywords and usually doesn’t offer value to a website visitor; it simply exists to increase ranking.

On one hand it is assured to get high rank in search engines using Black Hat techniques, but on the other it is true that it has short life. Any time your rank can come down and your website can simply be banned by search engines. Black hat technique provides ranking to your site for some time but after some time your site is blacklisted by search engine.