Tags are a product of the blogging revolution and primarily used in 2.0 and blogging platforms.
Tags are used to help web surfers find you page on the internet, they could be the same as your key-phrases but not always.
Keywords are the terms that directly tie to or illuminate your article, commonly found prominently in the page content and in the title and header tags of your document.
When a web user types a phrase into their browser search, you are hoping your site comes up in the first page of search results. When you site is opened your content should reflect the thoughts and answers that they were searching out.
The keyword is the object of the search.
The tag is the general term used to draw a certain niche of users.
Tag Examples (insurance,investments,politicians)
keywords Examples (whole life annuity policy,equity mutual funds,conservative party candidate)