Once keywords have been decided for site one has to come up with a strategy to target those keywords across site. Here is a primer on that.Keywords Targeting Strategy for Keyword of Single word: -------------------------------------------------------
Keyword of Single word is useful to attract general audience and helps in getting high rank ,if web site is new. Keywords Targeting Strategy for Keyword of Single word is that they should be more used in root level pages or top level domain pages. This is because these pages are ones that attract general traffic & are generally pages which do not specify specifics. Hence single word keywords based on themes can be targeted for on these pages.
Keywords Targeting Strategy for Keyword of Multiple words: ----------------------------------------------------------
Keyword of Multiple words are useful for attract targeted audience therefore should be used topic wise for each page according to subject of that web page. Relevant set of Keywords should be use in Title tag, Header Tag, Meta tag, Body tag, Alt tag, Anchor tag, Comment tag and in url (uniform resource locator) of that specific web page. Use underscore or hyphen to differentiate Keywords. These keywords are normally targeted upon in deeper level or sub directory level pages.
Keywords Targeting Strategy for Keyword based on Theme: ------------------------------------------------------
Keyword based on theme is useful to attract targeted audience therefore they are strongly recommended to be used. Typically, although it is not a hard and fast rule but in theme based keyword we use general keywords in root level and uses specific keyword in directory level.
Overall one can safely say that in keyword targeting one uses a dart board strategy. Wherein smallest circle attracts your core audience & hence should have theme oriented multiple word keywords. As we move up on theme (dartboard) circle ( traffic) tends to get larger & keywords tends to get simpler( singular) even though they are theme based.
KEYWORDS and KEYPHRASES usage in Domain Name: --------------------------------------------
Keywords and keyphrases use in Domain Name & urls of directory pages is also a factor in Search Engine Optimization (SEO) as well as it helps to inform targeted audience, about sites content . Therefore, special care should be exercised in choosing a domain name. All search engines start reading each web page with its respective domain name.
Having said that, let me add that there is a raging debate amongst seo community to determine exact importance of keywords in domain name. One camp believes that it is hugely important to have keywords in domain whereas other maintains that brand building domain name is more important than keywords incorporating one.
Whether keyword is a factor or not is debateble however it has been observed that domain name extensions do definitely play a part in rankings. Search engines ( specially google) have a predilection for sites having extension .gov,.edu,.mil in domain name. Search engines believe that information available at these domains would have a greater likelihood of being authentic as no commercial interest is served here.