Dead Link: A Dead Link is a Hyperlink to a page that not working no longer exists from any more on your webpage or site cause of server is down and page has moved this problem is shown like HTTP Header Status code is “404”

Deep Link: Deep link that is directly link to another part of the site or link to the another web site home page and its Linking that guides, directs and links a click-through searcher to a very explicit and appropriate product or category web page from search terms and Pay Per Click ads.

Doorway Page: Doorway page is a technique which is specially uses for drive traffic and brings keywords into high ranking. Its not create any good information for human being just make for search engines optimization in order to rank high for very specific keywords this technique has been unnecessary this all techniques has been spam by search engines.

Database: Data base is an organization collocation of data and it’s a storage area of all information about web site and web site content.

Directory: A directory is a web site that restrains a lot of categorizes and arrange by a topic from where you can list your web site in the particular category which is related to your web site this techniques search engines likes so much.

Description tag: Description tag is HTML Tag appears in Meta tag which describe all information about webpage. It doesn’t display on content page but it is to inform the search engine so that page can crawl correctly.

DMOZ: DMOZ is known as Open Directory Project. it’s a very popular directory and lots of human edited the web site in this directory. AOL Search engine is the owner of this directory.

Duplicate Content: As the name Duplicate content you must have been aware that it’s for the content which is already used in another web site or more than one web site or web page. It’s has negative effect on search engines because search engines don’t like that page or content which is already used by another site or another page which makes seo value will be very low of duplicate page or content.

Dynamic content: Dynamic content known as that content which change automatically and it depend on database and user information. Their are different types of dynamically url’s ends with .asp, .cfm, .cgi or .shtml

Domain Name: Domain name is a website address and URL as articulated in hypertext transfer protocol code.