Meta tags forgotten: "NOODP" "NOYDIR"

By Adrián Coutin

Short History

Backlinks from directories were links with high value for any web pages. Directories as Dmoz and Yahoo! were used for link builders as main sources of quality links some time ago.

Dmoz was the most important directory for Google. In fact it was the  Google Directory source some time, when directories were used as information source. Dmoz is, in fact, a directory edited for humans so linkbuilders can't manipulate very easy. I remember some years ago, probably 2008, that SEO expert Danny  Sullivan said that obtain an link from Dmoz is the same that win the lottery.

Yahoo! Directory, it was the beginning of Yahoo service, was a good directory  created for expert librarians. It had a high quality classification system that not only was a high quality source of links but also a good description of websites linked in it.

Google, assuming that these directories were sources of reliable information so in some circumstances, Google uses descriptions from these directories as the title and snippet for a web result.

Others search engines as Yahoo and MSN supports both meta tags during 2006.

Meta tags "NOODP" "NOYDIR"

In July 2006 Google supports new meta tags: "NOODP" and "NOYDIR" which help to avoid uses descriptions from both directories.  NOODP meta tags is oriented to block the use of descriptions from Dmoz directory and NOYDIR meta tags blocks descriptions from Yahoo directory.

How these meta tags were used (and you can see yet in many web sites around Internet)?

So in 2006 If you don't want the Google uses descriptions from DMOZ directory just needed to add the following meta tag:

<meta name = "googlebot" content = "NOODP" />

In case if you have this problem with Yahoo:

<meta name = "slurp" content = "NOYDIR" />

Did you need block descriptions from Dmoz in MSN? Just needed add this meta tag:

<meta name = "msnbot" content = "NOODP" />

Of course it was 2006 because in 2014 nobody knows that slurp and msnbot were the spiders from Yahoo and MSN search engines. 

Finally if a webmasters or SEO specialist wished  to solve this problem in all search engines with just one line of code:

<meta name = "robots" content = "NOODP, NOYDIR" />

Meta tags in 2014: No DMOZ nor Yahoo

As you can see the solution was easy and helped to show your own descriptions of Web, avoiding to confuse the audience.

 However it was a problem in 2006. Now Dmoz is a degraded directory and Yahoo Directory doesn't exist anymore.

So if you find them in web pages code don't worry they are meta tags forgets.

More information about how to use meta tags in : Google Webmaster Central blog.