Penguin update renders OSE & Majestic link data unreliable for link cleanup

  • 0
  • May 14, 2012
Patrick Altoft

Patrick Altoft

Director of Strategy

Following on from our blog post recently about cleaning up unnatural links we’ve been doing some research to understand which tools are best to use for finding bad links to your site.

The primary tools that most of us know and love for link analysis are Open Site Explorer from SEOmoz and Majestic SEO but we have recently found that these tools (even if their results are merged together) are not able to find the same level of unnatural links that Google is aware of.

The problem with OSE and Majestic is that they crawl the web starting with the highest authority sites and build an index with the priority given to the best quality domains. They have chosen not to fill their index with millions of low quality spammy sites. Unfortunately these millions of spammy sites are the very sites that we need to know about to clean up link profiles.

We performed some analysis to find the number of unique linking domains across 50 of our clients via OSE, Majestic and Google Webmaster Tools and found the following data:

  • Open Site Explorer – average 1245 unique linking domains
  • Majestic – average 1225 unique linking domains
  • Google Webmaster Tools – average 2049 unique linking domains

On average, OSE and Majestic only offer 60% of the link data that WMT offers. Not only that but the links that OSE and Majestic are usually missing is the very data that sites need if they are trying to find link spam in their profiles.

The only way to perform a full analysis is to merge data from the three sources together but if you want to use one tool then the best one to use is clearly WMT. We’ve seen examples of sites where the SEOmoz & Majestic data shows a nice and trusted link profile but Google is reporting some very dubious links that SEOmoz and Majestic were not aware of.

Rumour has it that SEOmoz is going to be building a spam detection algorithm but until they can dramatically increase the size of their index to find all the spam links this system cannot be reliable.

In the past it was a quite reasonable decision for OSE and Majestic to prioritise the crawling and indexing of quality sites at the expense of blatant spam sites because the tools were designed primarily to help with competitor analysis. Unfortunately after the recent updates it’s far more important for SEO’s to be able to find the bad links in their own profiles than it is to find their competitors good links.

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