A keyword suggestion tool is an online resource which produces a list of keywords appropriate to a particular subject. These keywords can then be used prominently on a website in the hope of attracting visitors who look for those terms through a search engine. At its most basic a keyword suggestion tool is a glorified thesaurus. More advanced tools are based around data about the actual search terms people are using online and the rates advertisers are willing to pay to appear on relevant web pages.
A keyword is any word or phrase which people type into a search engine. Many website designers, particularly those with commercially-based sites, will aim to produce a range of pages to attract people who type different variations of the same phrase. A keyword suggestion tool can produce alternatives to your primary keyword.
The best keyword suggestion tools will give you data about how many people have searched for each suggestion. In some cases this data can be filtered by date so that you can tell the difference between a keyword which is consistently popular and one which may be extremely popular but only for a short time. If your site hosts pay-per-click based advertisements, you may want a tool which provides details of the current rates advertisers are paying for clicks on adverts appearing on pages which emphasize each keyword.
Its important to remember that the suggestions from a keyword suggestion tool may not be relevant for a site. This is particularly likely to be the case if the primary aim of your site is to make money from visitors clicking on adverts. For example, if you run the term "personal injury" through the tool, it may note that the alternative "personal injury lawyer Manhattan" is very popular among searchers. This may not be useful for an ad-based site as somebody searching for this term is likely to be looking specifically for the website of an injury lawyer in Manhattan or a guide to the best injury lawyers in Manhattan. Even if you use this keyword, these people are unlikely to visit your site if it is simply a general guide to personal injury cases.
One feature to look out for is the ability to get keyword suggestions based on users in a particular country. This is useful if your site is aimed at providing information or selling a product or service to people in that country, for example where the law prevents you selling across national borders. If you are promoting high value products, you may wish to look for keywords used by people in developed nations only as they are more likely to go on to buy.