BlackHat SEO refers to tactics and techniques which focus on achieving high SERP positions without following the search engine guidelines. Some of these tactics and techniques are parasite hosting, keyword stuffing, cloaking and sneaky redirects, hidden text and links, paid links and doorway pages. None of these tactics works if used independently, but if they are used all together, they have the potential of getting a site rank high. Remember, though this is temporary and will not last. A good SEO strategy is focused 100% on white hat SEO.
BlackHat SEO can achieve top search results very fast, targeting many keywords and it is also very easy to do for low-competition keywords. However, they also come with significant disadvantages: they are easily detectable by search engines and users; they only work on the short term; moreover, they put the sites that use them at risk of being penalized by the search engines. Google does not approve of these blackhat tactics because they work well, even if on the short term, and, in doing so, they make paying Google advertising money unnecessary.
Not all blackhat SEO tactics are created equal. Some of them are difficult to remove once the site you used them for is penalized by Google. The ones that are easy to fix include hidden links and hosted doorway pages when added to a domain you control. On the other hand, comment spamming is impossible to fix because you have no way to delete the links you spammed on other blogs, they could be live for years on end.
2014 seemed a good year for a few select blackhat techniques, that are derived from whitehat techniques with a little twist. With 2015 here it is best to steer clear of these techniques altogether. Things like buying twitter followers, google plus circles, facebook likes and Instagram Followers are things of the past. To effectively rank and keep rankings in 2015 white hat SEO is imperative.
The expected updates of the Google algorithms could swipe away many sites that use blackhat techniques. It is only a matter of time as when they to it and it is also a numbers game, as not all sites will be penalized. SEO is not dead and replaced by social media marketing, but it is changing at a fast pace. We just need to adapt to even its slightest changes and we will prevail, either in the white, gray of black spectrum.