Meta tags are special html tags placed in the head section of a web page to control how search engines list and index the site. Meta tags are generally used to give search engines detailed information about your site whenever they come crawling your contents. Many information can be contained in meta tags and this make can go a long way in boosting your pagerank if properly implemented.
Different meta tags perform different functions. There are meta tags to tell search engines about your site main language, general description, relevant keywords, whether to index web pages or not, etc.
An example of Meta tag is given below:
<TITLE>The Unknown Site</TITLE>
<META NAME="description" CONTENT="This site is sbout unknown stuffs you probably didn\'t know before reading this stuff.">
<META NAME="keywords" CONTENT="unknown things,stuffs,abc,xyz,blah blah blah">
<META NAME="robot" CONTENT="index,follow">
<META NAME="copyright" CONTENT="Copyright © 2011 Unknown Inc. All Rights Reserved.">
<META NAME="author" CONTENT="Unknown Author">
<META NAME="language" CONTENT="English">
Having proper information in your meta tags is an on-site search engine optimization step. It must be detailed and the information contained therein must be accurate or you might get penalized by including wrong information such as inexistent keywords. Also, you must be sure the content of each meta tag content does not exceed 100 characters. It should actually be much less according to SEO experts. It’s not the quantity that matters, but the quality.
Almost all the popular search engines like Google, Yahoo, MSN Search, AOL Search, AltaVista, AllTheWeb (FAST), HotBot, Lycos, Infoseek (Go), Excite, and WebCrawler support Meta tags and it is important to have well made meta tags because they can help increase your Search Engine Position.
You can edit the one I posted above or use this Online Meta Tag Generator.
How To Implement the Meta Tags on Your Blogspot/Blogger Site
1. Login to your blog and click on design
2. Click on Edit HTML
3. Search for </head>
4. Just above this, paste all the meta tags.
3. Save your template.