Meta-tag spam is the unethical SEO technique. Many internet marketing companies use this technique in providing their services to their customers. In order to understand it first of all you should know what are Meta-tags? Meta-tags are html content search engine spiders.

These tags are used to quickly reference the content of the web page of any website.
Now I will tell you how internet marketing companies use this technique. These companies actually spam meta-tags “keywords” element with a long list of repeated search terms.

This list of terms is then repeated again in the “description” element of the meta-tags.
I think you would have understood the unethical aspect of this technique.

The ethical way to use meta-tags is to use relevant elements. In a right way the relevant keywords and descriptions about the web page are placed in the meta-tags.