Understanding the Panda algorithm

The change in the Google ranking, called Panda from the name of an engineer, impacted 11.8% of US website with poor content, not original or not very useful.

Rabid panda

"We want to encourage a healthy ecosystem..." Google said.

Panda is a program launched manually from time to time by Google to assess the "quality" of sites, that was integrated to the organic algo in January 2012.
It results in an overall score assigned to the site that is taken into account by the algorithm to rank pages.
No other criteria of the algorithm does alter this score.

Google has a long-term vision. Firstly webmasters will react and adapt their site to these new conditions. Even if that make it less convenient for the user.
And the criticism that the firm has suffered - we remember the joke of the April 1 on the Yacht called Adsense of the CEO of Demand Media - hurted it and it had to react.

Dates of Panda updates, the first two are official, the following are estimated:

Criteria of the Panda algorithm

The criteria used to enhance the "quality" of sites, based on infos given by Google and experience of webmasters:

Factors such as bounce rate, useful content visible above the fold beside advertising are criteria that the general algorithm takes into account and not Panda.
Panda is a separate program that requires vast resources because it analyzes the content of the pages and compares them to detect what is original and what is widely published.
In addition to originality, content is confronted with requests, and the same page can answer many queries. It is certain that Google uses semantic analysis techniques to compare the content of the pages and go beyond the similarity between sentences. This has been unveiled by a team member on a forum. Panda's role is to perform the heavy analysis of contents.

This does not prevent the engine to use different shortcuts and give a premium to the most popular sites, as it usually does, so they can avoid being penalized by Panda. It depends on the ratio of useful content too.

Pages considered of lower quality are now less often visited by crawlers (according to Matt Cutts). You can therefore by looking at the logs have information about that.

Collateral damages

A side effect of the two updates is that sites whose content is often copied, have been affected by this change, Google being often unable to distinguish what is original and what is the copy. This has shocked webmasters.

A new word has appeared on forums, "pandalized", which applies to a site that has lost most of its traffic as a result of this update.

If Mr. Panda had wanted to effectively combat spam, it took into account low content pages with a lot of advertising, but advertising is out of the equation for Google. We understand why.
As a result, e-commerce and educational sites are penalized: their content is not original enough! A priori, two e-commerce sites with the same product are equal, but one will be valued as the original and the other a copy ...

How to modify a site to avoid a Panda penalty or reverse its effects

What to do when hit by the Panda update?

From Google:

"Low-quality content on some parts of a website can impact the whole site’s rankings, and thus removing low quality pages, merging or improving the content of individual shallow pages into more useful pages, or moving low quality pages to a different domain could eventually help the rankings of your higher-quality content."

But all experts agree that it is not possible to cancel the penalty, and this is confirmed by experience, without to change the content of existing pages and adding new content.
When a site is pandalized, it is not the poor content that is downgraded but the whole site. Then deleting pages with poor content does not fix the issue, to the contrary, you lost visits (except for pages of tags or content duplicated from other sites).
So we can not restore a site that is penalized, without adding a new content founded on new bases, creating like a new site.

  1. For pages whose engine cannot understand the interest for the user enrich their content. Do not delete them.
  2. Personalize the content. Use your own words. And, I talk to bloggers, remember your essays in school, the teacher did not ask you to copy the subject or the answer of someone else, but to give your own ideas.
  3. Add one external link to a quality article on another site  with a critical and personal advice. A different link in each page.
  4. If the site has no system of comments, add a comment or an analysis which will attempt to adopt an unexpected perspective.
  5. Take care of the user experience, the desire to see other pages, to return to the site.
  6. Add an original image in every page to improve the user experience.
  7. Make sure your content offers something useful, so new (make a search for similar content). Always ask what your page offers more than others.

You should know that changing the existing content will not suffice to undo the effects of the penalty. This is especially new unique content that will do. And diversification of the content.
This will require much work, but you will be consoled in thinking about content farms which have million pages to modify...

Conclusion

The most important new fact which makes the results incomprehensible to webmasters, wich has been officially confirmed by Google, is that if a part of a site is considered of poor quality, the whole site will be penalized. So pages of very good quality will be less well positioned in the SERPs behind pages of other sites of lower quality!
It's hard to admit. This goes against the doctrine from Google that you have to make sites for users, not for the search engine.

See also

More infos