what is the use of NOODP & NOYDR in Meta Tags ?

[Henry Smith]

NOODP and NOYDIR Meta tags give you more control over the descriptions of your site that appear in search engines. Sometimes search engines like Google, Yahoo and MSN use Open Directory Project (ODP or DMOZ) to generate the description (snippets) that appear in the search results page.

As the web is fluid is ever changing there are chances that Webmaster would like to change or update the descriptions of their websites at regular intervals. To do this and stop search engines from generating site descriptions from ODP or Yahoo Directory we use the NOODP and NOYDR Tags.