What is a Meta Tag and do they work?
Meta tags are similar to that of an index of a book. They are used to describe your HTML document.The 3 most important being title, description, and keywords.
There are several search engines that no longer place relevance on these tags. For more on this, see Types of Search Engines.
The title tag is important for your visitors, but search engines index and rank pages by the contents of these tags. When users search for keywords in a search engine, the engines process the request by searching for documents that contain these keywords, and rank them accordingly, then return the results to the user.
Meta tags do work, however there is more to their creation and usage than placing a keywords into the tag that you want your web site to be found under.
One of biggest mistakes with using meta tags is lack of relevance. There must be a relevance between the keywords you are trying to target and the text of the page. The keyword you are trying to target must be used throughout the web page for it to be effective.