(This is #2 in my SEO Basics articles for Gooruze. The first covered Search Engine Spam.)

With new Web users constantly creating new sites or new blogs, it's no surprise to see and hear so much confusion and uncertainty around the Web about what meta tags do, and how to use them. This article will provide the basics that all webmasters need to know.

The Basics

There's one meta tag you really should/must use, and many that rarely matter, if at all.

• "Description" meta tag - This one you should/must use. Every page on your site should have a unique description that corresponds to the visible content of the page. This will often show up in the SERPs as your site’s “snippet,” so make sure you write these with the searcher in mind. A well-written Description meta can be the trigger that gets searchers to click.
• “Keywords” meta tag - Hardly ever matters, if at all. It has no bearing on your rankings. I still use it for some client sites, and don't bother with it on others. Google and MSN ignore it entirely, while Yahoo and Ask reportedly take a look at it. But they'll only use it as an absolute, final, end-of-the-line, last resort to help figure out what a page is about. If you decide to use it, don’t go overboard -- keep the keywords list short. I prefer to use it for misspellings of common words.
• "Other" meta tags - there are all kinds of other meta tags you can use, but none have any impact on SEO.

Any official word?

What do the search engines say about meta tags?

Yahoo recommends you use the Description tag in its Search Help pages. (Astonishingly, they also recommend using the Keywords meta.) Google also wrote about using the Description tag effectively on its Webmaster Central Blog.

Beyond that, when I interviewed former Yahoo Search team member Jon Glick last year, he confirmed that the Keywords tag has no real benefit and is more to help with matching, not ranking.

Real-Life Examples

On a real estate agent/broker site, for example, you might use the Keywords tag like this: Say the agent covers 10-12 different cities/towns, but on the web site you may not have content about all 10-12 towns. In that case, you might use the Keywords tag to make sure the full list of localities is covered.

I also used to regularly reference Nordstrom.com on this topic. For a long while, this is what their Keywords meta tag included:

Nordstrum, Nordstroms, Nordstrums, Nordstrums.com, Nordstrum.com

That was perfect; a simple list of several common misspellings. Alas, now it seems they've decided to stick a bunch of useless words like "sale" and "shoes" and "online shopping" into their Keywords tag, and I really can't use them as an example anymore.

Conclusion

Your focus, ultimately, should be on the Description meta tag. It's the one that searchers may see while looking at SERPs, and if written correctly, can help attract more clicks than your competition.

Postscript

The page title is not a meta tag, and wouldn't be appropriate for inclusion in an article about meta tags. I'll cover page titles in an upcoming SEO Basics article.