On Dec. 31, an integral part of Yahoo's history -- the Yahoo! Directory -- will be shutting down for good.

After 20 long years of being an inimical part of Yahoo!, the hierarchical website directory that was created in 1994 by Stanford graduates David Filo and Jerry Yang, will close shop.

Yahoo! announced the directory's retirement via a blog post on Sept. 26. The company will also be discontinuing two more products: Yahoo! Education, a portal for education services, and Qwiki, an app that creates short movies via video on mobile devices.

"Yahoo! was started nearly 20 years ago as a directory of websites that helped users explore the Internet," revealed Jay Rossiter, senior vice president for the cloud platform group. "While we are still committed to connecting users with the information they're passionate about, our business has evolved."

In the pre-Google era, the Yahoo! Directory search tool was a digital version of a directory, albeit for websites. The websites were listed into categories, such as science, business, art, computers, events, environment and nature, education, and entertainment, among others.

These listings in turn had several tiers or sub-categories and sub-sub-categories; for instance, when searching for video games, one needed to navigate to "computers," followed by "games" and then "video games." Instead of putting in keywords as one does on search engines now, a user had to search via category.

The decision to axe Yahoo! Directory, Qwiki and Yahoo! Education is likely an effort from Yahoo! to restructure its business. This is not the first time Yahoo! is retiring a product that no longer serves its purpose. In the past two years, Yahoo! has "sunset" over 60 products in a bid to streamline business operations.

With technological advancement, closing down products that are less relevant to Yahoo! enables the company to move resources to areas where they are needed more, disclosed Rossiter.

"Yahoo! [has] focused on our core products -- search, communications, digital magazines, and video -- we can deliver the best for our users," noted Rossiter.

Rossiter also said that after Dec. 31, advertisers would be "upgraded to a new service;" details of which would be disclosed to those concerned.