Keywords are words or phrases that describe the content. They can be used to describe images, text documents, database records, and web pages on the basis of metadata.
A user can easily “tag” pictures or text files by using keywords which are relevant according to their content. Later, these files can also be searched using keywords, while this makes it much easier to find files.
For example, a photographer uses a program such as Apple iPhoto to tag his nature photos with words such as “nature,” “trees,” “flowers,” “landscape,” etc. By tagging photos like this, he can easily locate later by simply searching all the flower pictures to the keyword “flowers”.
Keywords are used in the web mainly in two ways,
1) first as search terms in search engines, and
2) words to identify the content of the website.
1. Search Engine Search Terms
Whenever you do some search in a search engine , then in this way we type keywords which tell the search engine what to search.
For example, if you are searching for used cars, then you will enter “used cars” on the keywords.
Then the search engine will automatically show such web pages in SERP ( Search Engine Result Pages ) which is relevant according to your search terms.
While the more specific keywords you use, the more specific (and useful) your results will also be. So if you are searching for a specific used car, then you have to enter some keyword such as “ Blue Honda Maruti Suzuki used car ” from which you will get the best accurate results.
Many search engines support boolean operators which can be used with keywords so that the search can be refined more.
For example, you can search “ Apple AND computers NOT fruit ” if you only want information related to Apple products and not Apple information of a fruit.
2. Web Page Description Terms
Keywords can also describe the content of a web page for which the keyword uses meta tag. This tag is placed in the HTML of a page in the section and contains all the words that describe the content of the Web page.
The main purpose of keywords meta tag is to help search engines in identifying and organizing web pages.
But since now webmasters use inaccurate tags to get higher search engine ranking, many search engines give very less importance to keywords meta tag when it comes to indexing pages.