I believe that this page will answer your question: http://websearch.about.com/od/seononos/a/spamseo.htm Remember, when life gives you questions, Google has answers.
Here is some brief description of Blackhat SEO techniques: http://sitemonetized.com/Top-Black-Hat-SEO-Techniques/
Don't even waste your time looking it up. Trust me, I've spent years doing blackhat SEO and you know what, it's damn hard work! Much easier to build web assets with real content, real links and real people promoting your stuff for you. Anybody who says otherwise is making money by perpetuating the spam culture that gives the industry a bad name. Look into guest posting, article marketing, content creation and dofollow blog commenting as a way to dip your toe into real SEO.
ah well, either blackhat SEO or whitehat SEO takes a whole lot of knowledge+effort. It's always better to hire someone to do this kind of thing rather than do it on your own, unless you're a pro. The true is, blackhat SEO works, and can give you good results fast, but they won't last very long. Conversely, "whitehat SEO" won't give you instant results, but will pay off over a long period of time.
Black Hat SEO which means pushing the limits of the terms of service and guidelines of the search engines to gain the best result possible. Black hat techniques are sometimes referred to as search engine spamming. One example is repeating an important keyphrase many times on the homepage. Another is using text that it is the same colour as the background of the page, so the keyphrase is visible to the search robots and algorithm, but not to the human reader. Engineering pages for robots is a practice known as ‘cloaking’. Other examples of spamming which are well known are doorway pages and link-farms.
as I've explained many times, 'black hat' is a term used by people to describe practises they consider to be 'dubious'. They normally hold this opinion because the search engines tell them it is 'bad'. The search engines don't like anything that their algorithms can't automatically deal with, and classify this stuff as 'blackhat' in order to scare little newbies into not doing it, which makes the engines lives easier. Once they CAN deal with it automatically, it's no longer 'black hat', it's "stupid". Creating 'doorway pages' nowadays is 'stupid'. repeating the same keyword in background color font is 'stupid'. At time of writing, what's 'black hat', rather than 'stupid' is untraceable non-reciprocating link structures, grammatically correct text spinning, that kind of thing.