If you've been looking into marketing your website, and trying to get it higher in the search engine results, you've most likely read some articles and seen people talking about Meta Tags. A lot of writers may not bother to fully describe these beasties, simply assuming that you just know what they are.
To describe what the Meta Tags on a webpage are, we'll start at the beginning. There are two main sections to a webpage: the head, and the body. The head is a section that contains general info about the page and some info for what type of page it is. One of the things in the head is the page title that goes at the top of the page's window Internet Explorer, Firefox, Opera, Safari, etc... Also in there are the Meta Tags.
The main purpose of the Meta Tags is to describe the various aspects of your page. Is it public, should the search engines index it (which is yes by default), when was it created, who is the author, and most importantly, a description of the page, and the keywords for the page.
Those last two are the ones we're going to focus on here as insofar as SEO (search engine optimization) is concerned, they are the two most important. We'll start with the Meta Description.
I'm sure that as you have used the search engines such as Google, you'll have noticed that the title of each result is the same as the title of the page when you click the link. But if you were observant you may have spotted that sometimes the description under that listing on Google is not to be found anywhere on the page when you get there. That's because it's provided by the Meta Description Tag. This tag can contain up to 250 characters of text that describes your page and what it is about. You should make it compelling, and make sure to use your keywords at least twice (depending on how much of the 250 characters you use).
Here's what the tag looks like:
Site's description here." />
(If you see strange text at the beginning and end it should be a less than symbol on the left and greater than symbol on the right)
Write out your description and if you have to use any double quotes (") put an in front of them.
It's very important to have this tag in place as if you don't, the search engines will simply mash together the first 250 characters of text they see on your site and you can imagine how that could read when all strung together.
The next item is the Meta Keywords.
There's a lot of debate around these puppies as they used to have a lot more significance than they do now. About a decade ago the keywords you set were all that the search engines looked at to find out what your site is about. Of course it didn't take long for people to abuse them and put totally irrelevant things in there (such as their competitor's names) just to get traffic.
These days the search engines do use them to get a handle on what you are trying to target, but if you abuse them, the search engine penalizes you. Here's an example.
Say your site is about furniture and you use the keywords "couches, chesterfields, end tables, lamps". These are decent enough keywords but only if your website contains them with significant density. Your first keyword should comprise of 5% of the total words on the site. This is referred to as the 'density'. If you only use it once, or worse, not at all, the search engines will think you are being misleading and dock you for it. If the word appears too much, say 10% of the time, they'll think you are spamming and dock you as well.
Using Meta Keywords is very good, and very powerful, but if you don't take care to make sure your densities are correct, or that the words appear at all, you'll end up causing yourself more harm than good.
Meta keywords are entered in a comma separated list, and are formatted like this:

(If you see strange text at the beginning and end it should be a less than symbol on the left and greater than symbol on the right)