Meta Tag Overview
What are meta tags?
They are pieces of information that are inserted into your web page's code that offer information about your website. Besides the Title Tag, which you can see in the top of the browser, the rest you do not see, yet includes some important pieces of information, like what "character set" to use or whether a web page has self-rated itself in terms of adult content, for example. There are many different meta tags, but I will only discuss the most important ones as they relate to Search Engine Optimization.
The Title Tag
This isn't really a meta tag, but is lumped into the the whole meta data set. This appears in the top of the Browser's window (called the Reverse Bar) when you view a particular web page. It is used when you save a "Favorite" or "Bookmark", but the Title Tag is very important from a Search Engine Optimization point of view. It is a critical factor for Search Engines and how your website ranks. It is used as the linked text in a ranking and should be thought out with great care. Keyword's are vital to having an effective Title Tag. Tip: make sure you put the proper and relevant keywords, or phrases here, and only use about 7-10 words.
The Meta Description Tag
This tag allows you to influence the description of this particular page for the web crawlers out there that support the tag. I say this because Google ignores the meta description tag and will create its own description for the page, usually by pulling content from the page itself (so make sure you write well optimized content). Tip: you can typically take the first couple of sentences from your body copy of the page for this.
The Meta Keywords Tag
The meta keywords tag provides an area to write descriptive keywords for that particular page for crawler-based search engines that use them. Most major crawlers ignore them, because in the early days of Search Engines, some websites would stuff many many keywords here to garner better rankings. Because of this "keyword stuffing" most have since taken it out of their steps when crawling a site. Tip: because some crawlers will actually harm your rankings for overuse of the meta keywords tag, I would only put about 5-7 keywords there and be done with it.