Meta tags are just one of many optimization techniques that should be used to effectively prepare your web pages for the search engine spiders. A number of the major search engines use meta tags to "filter" query results.
Two of the meta tags you should be using are the keyword meta tag and description meta tag. The two meta tags provide additional information to the spiders for ranking and indexing. By inserting meta tags your site won't instantly be indexed and rank well, it is a tool in the optimization process that should be used and managed.
Remember to effectively use meta tags they must be properly formatted, positioned, and continuously monitored to achieve maximum search engine results.
