ZOMDir > Blog

Monday, 17 November 2014

The Directory Yahoo!

A few days after the news that Yahoo! will stop with their directory I read a tweet that suggests to copy Yahoo! and make it available as a subdomain of ... another link directory. 

I wondered is that makes sense, so I decided to find out what the quality of Yahoo! is. Here are my findings.


Yahoo! has a structure based on subjects which is sometimes mixed with locations. The generic term used is categories. The mix of subjects and locations is available in two flavors. For example:

1. regional > countries >  belgium > [subjects | provinces | regions]
2. news and media > newspapers > by region > countries > belgium

In this structure there are many cross references. When you go to the category Arts you will find some categories ending with the @ sign. This is an indication that this subject belongs to a different category. See the example below:

I have tried to figure out how much unique categories there are. My estimation is that there are 55,000 to 75,000 categories.

Links per categorie

The number of links per category varies. There are a lot categories with a few links. For example the following category has only two links.

Regional > U.S. States > North Carolina > Cities > Durham > Education > College and University > Private > Duke University > Departments and Programs > Center for Documentary Studies

However there are also categories with nearly 1,000 links like the category:

Arts > Visual Arts > Painting > Artists > Personal Exhibits > Oil

To handle this large number of links Yahoo! used pagination. For the above mentioned category there are 49 pages with 20 links per page.

Due to this variation it is very difficult to estimate the total number of unique links on Yahoo! Therefor there is also a large variation in my estimation. I think that there are 1,000,000 to 3,000,000 links mentioned on Yahoo!

Yahoo is probably smaller than DMOZ

As a reference on the homepage of DMOZ.org is stated that there are 4,148,153 sites in 1,023,413 categories. That said, the conclusion is that Yahoo! is smaller than the open directory project.

Quality of the links

To get an idea of the quality of the links I made a few samples. 

Sample 1. Category: Arts > Humanities > History > Genealogy > Heraldry

In this category there are 13 sites mentioned. From these 13 sites there are:
  • 8 working links
  • 3 broken links
  • 2 links to a parking site

Sample 2. Category: Arts > Humanities > Literature > Museums

In this category there are 38 sites mentioned. From these 38 sites there are:
  • 33 working links
  • 3 broken links
  • 2 links to a parking site

Sample 3. Category: Arts > Performing Arts > Dance > Contemporary > Breakdance

In this category there are 11 sites mentioned. From these 11 sites there are:
    • 5 working links (although 2 sites stated that they are closed)
    • 5 broken links
    • 1 link to a parking site

    Sample 4. Category: Science > Ecology > Tropical Ecology

    In this category there are 14 sites mentioned. From these 14 sites there are:
      • 10 working links
      • 3 broken links
      • 1 link to a parking site
      It depends on the chosen category how high the percentage working links is, but it is clear that you will find broken links everywhere. 

      Based on these findings it is clear that the quality of Yahoo! has vanished. There are simply too many non-working links. 

      It is a pity, but it is logical that the Yahoo directory will shut down.


      ZOMDir.com is a dynamic directory and a wiki
      Everyone is able to add a link in 10 seconds
      To learn more view this Slideshare presentation

      Monday, 3 November 2014

      604, that's not an error

      The internet is often a dangerous place. As an innocent surfer you will never know for sure what the result of a click on a link will be. Even normally trusted sites might be infected by malware due to malvertising (see also anti-malvertising.com), bot attacks or other nasty tricks. 

      ZOMDir tries to minimize the probability that you visit a site that has wrong intentions. Therefor all links at ZOMDir are checked with Safebrowsing at a Glance.

      At a regular base there is a content check. When a linked page doesn't load, is redirected or is probably unsafe to visit then this link will be removed automatically. When this occurs you will find in the overview of removed links the corresponding error code. In this list you might find also status code 604.

      Status code 604 indicates that it is probably unsafe to follow the related link. The reason might be that link is marked as suspicious by Google Safebrowsing or that this link is marked as unreliable at the Web Of Trust.

      That's all I can tell you now about this status code.


      ZOMDir.com is a dynamic directory and a wiki
      Everyone is able to add a link in 10 seconds
      To learn more view this Slideshare presentation