There are many techniques to improve the rank in search engines. Some of these techniques are ethical and some are not. Some give good content to readers and some build websites just to stand in the top of search engines listings. They don’t have any useful content and such kind of websites are was of time for users and don’t give any kind of information. Hence search engines have classified optimization techniques into two types.
1) White Hat Search Engine Optimization
2) Black Hat Search Engine Optimization
White Hat SEO:-
The techniques that are approved by search engines and those techniques that follow ethical are called white hat search engine optimization techniques. The websites that follow white hat seo follow the guidelines set by search engines and do not deceive its viewers and crawlers of search engines. It takes considerable amount of time to get good ranking by following white hat seo, but it in long term, it yields very good results. As the content will original and unique, most of the people like to visit the website again and again.
Some of the examples of white hat seo techniques are submitting the sites to directories, using proper keywords and key phrases in the content, optimizing Meta tags, obtaining back links from high rated and relevant websites etc…
Black Hat SEO:-
Black hat seo is exact opposite to white hat seo. They are unethical and cheat both its visitors and search engines. Some of these techniques redirect visitors to pages which are not at all relevant to the query. Black hat techniques will reduce the quality of search results of search engines. Hence search engines penalize the sites that use black hat techniques and will remove the sites using such techniques from their search index.
Some of the examples of black hat seo techniques are spamming the comments on forums, blogs, articles etc, stuffing the page with list of keywords in the page and hiding them with the background color same as the color of the text etc.
Detailed example of one black hat technique, Keyword stuffing and how it works
For example, if a website which is not at all related to cooking or food related articles, thinks of optimizing for FOOD using black hat techniques, then they write a text which contain only that keyword and hide them by using the background color same as the color of the text. So, the human visitor cannot see it because both the background and text will be in same color but crawlers or bolts can read them. When a user enters the keyword FOOD in the search bar, then the crawler will think that this site has some content related to FOOD and shows it in the search index. But the user will be confused to see a site which is not at all related to it and gets annoyed or frustrated.