Keywords - the theory

The term keywords will concern further to the words which are included in text HTML of the document and in prospective search of the user of the search engine, looking for the information on the subjects conterminous to subjects of the document.

Relevance

Search machines expect relevance of the text, building a frequency number{line} from words. The more often the word meets in the text, the big, in relation to search of the user, it receives relevance.

Depending on a level of a competition and a task in view the quantity{amount} of keywords can change from two - three up to ten. The the document is adjusted to smaller quantity{amount} of keywords, the these keywords can meet the greater frequency in the text, and the their relevance is higher.

Highly relevant documents are guided by two, three keywords, each of which meets in the text in the ratio close to 1 to 20 (5 %). The keywords meeting in the text with the greater frequency, can be perceived{recognized} by search engines as a spam.

Volume of a potential audience

Keywords should be selected in view of frequency of their use, at information search. As a rule, people use the first words which have come in a head. Also it is necessary to be guided by these words.

But the highest relevance of the document to search arises, when separate words, and phrases coincide not. It is desirable (but it is not necessary) that keywords entered into key phrases only.

As key it is necessary to choose phrases which with a high probability can be used by a potential audience at information search.

Competitiveness

The the big relevance they have keywords, the the big competitiveness give to the document. But the level of relevance of competing resources, because of lines of external factors (popularity, quantity{amount} of external links), can be estimated by search machines more highly. In this case it is necessary to use synonyms or words faithful.

At a deviation{rejection} from group of the most popular keywords there is a reduction of the size of a potential audience by some orders (1 - 3).

It is very important to take into account volume of the potential audience using for search keywords to which the document is adjusted. Otherwise the situation when the document will be focused on extremely not a significant audience is possible{probable}.

Use of common words (the automobile, the book, commerce) covers at once almost all users of a network looking for the information on these subjects. But also to compete it is necessary with all resources on the given subjects.

More specialized words (the carburettor, the volume, overdraft) will lower a level of a competition, but also the size of an audience will decrease.

At job with key phrases the volume of a potential audience also depends on the size of a phrase.

The on longer phrase the document, the below a level of a competition is charged, but also the size of an audience is less. To be guided by a phrase more than from 4 words it is not meaningful - few chances, that somebody will type{collect} her .

It is necessary to choose keywords so that at search the search machine gave out the list of resources (first ten), a part from which on quality (style, the information) concede to the positioned document.

But it does not mean, that it is possible enter at once in ten. There are some more factors, most important of which - external links and attendance.