Meta Tags are important for obtaining better results in search engines that use Meta Tags as part of their algorithm. But Meta Tags can hurt you as much as they can help if you don't follow some basic rules:

In general you should:

• keep your description under 30 words in length.
• keep your keywords to under 12.
• make sure your description contains some of your most important keywords.

What happens if I use to many keywords?
Some search engines will penalize your site if you use too many keywords. The term for this is called "keyword stuffing."

Why should I mention some keywords in my description?
Mentioning a couple of your main keywords in your description, body of the text on your Website, and in your page's title all help increase the relevancy of that particular keyword.