The META element is used to provide information about your HTML document; it is not meant to duplicate the structural information that the other elements, such as TITLE, convey about the document.
Therefore, the META element is not required for AltaVista and other Web spiders to index your web. To get your HTML pages indexed, visit the Web spider (keyword) sites of interest and register your page(s). The Web spider will visit your page and automatically construct its own index and summary of what is there. A site like Yahoo is a different kind of index site, a Web subject tree, that will not scan or index the contents of your site, but will, if your site is accepted, point to your web page(s) within its own structure.
Specialized sites may require or suggest that you use META statements to be effectively listed. In such case, you can use the META statements to provide special information. For example, AltaVista recognize the META element attribute Name with values description and keywords. These are useful if you would like to have AltaVista associate special keywords or description with your document. So, for example, if your page is about "the meaning of life," you could place these two statements in the HEAD element of your document:
<META Name="description" Content="This page tells you all about life.">
<META Name="keywords" Content="universe, life, everything">
There is not a standard list of fixed values for the values of the Name attribute of the META element. Many Web spiders like AltaVista will recognize the two values shown here, description and keywords. Note that it is considered poor Net etiquette to put misleading keywords in your META elements for the purpose of tricking users to visit your pages. While getting indexed in search engines is important, good web promotion techniques can have an even bigger impact on getting your web to the attention of its target audience.