Cloaking is where you show one thing to a user and then serve up something different to search engines. And blackhat seo is techniques that can work to help your site rank well but are only really short term stratergies as if you run black hat techniques too ling you run the risk of been caught and penalised. - Cloaking is a blackhat technique.
Simply put, cloaking is any process that involves presenting search engines with one set of information and the visitors with another. The copy presented to the search engines is highly optimized and hence the search but may rank it higher. When a visitor clicks on the link he is either redirected to a new location using CGI, JavaScript or Meta refresh tags or is tricked to enter a new page by using a mouse-over function.
Cloaking can bring you good traffic for awhile but never cloak on a website you care about because chances are you could get banned by Google.
I also have a good experience with cloaking, however, it is considered maliciously and illegal. I have used it in the past to provide search engines with access to videos to be able to index them (mostly for Yahoo Video Search) however, users with a prompt to pay to watch the videos. The videos were really there, so I used cloaking for search engines to be able to know what (exclusive) videos I had availble for download. It returned up to 60.000 unique visitors per day from Yahoo Video Search and Altavista Video Search. I am not sure if it was really illegal what I did, because it enabled people to find exclusive videos via video search systems that they otherwise would not be able to find. For 'promotional' practices for a website or information it is totally difrent. A few years back even BWM.de got banned for it and it will only harm your visitors their user experience since they don't find what they were looking for.
We cannot expect traffic for more times using black hat technique. Search engines seriously penalize the websites and the results no traffic from search engines.