How Does Panda Work?
Enough data has been collected now to make educated guesses as to Panda’s operation. Because it is resource intensive, it analyzes a copy of the live index and finds positive matches for characteristic low quality sites. If it finds a match (by finding low usage statistics) it may also trigger a PageRank analysis, or even a manual review. Think of the Panda algo like the tax man, who can ruin your life on his own, but may also call the police if they find questionable background information. Unlike PageRank which runs constantly, Panda changes have been applied on a 2-6 week schedule. To get out of Panda, issues need to be fixed quickly and the Panda filter run again. It is much better not to get hit in the first place as some sites can never recover because they just don’t have the quality to warrant that kind of traffic for those important queries.Bounce Rate: +50% Index or Sitewide Average Bounce Rate
Our studies show this is one of the triggers for a Panda review. If your “back to SERPs” bounce rate, or your average sitewide bounce, exceeds 50%, this may trigger a deeper check (and a “Pandalization” for any given related query, or family of queries) as it may indicate low quality pages. If the majority of your pages have poor usage metrics, this can be enough to cause a Panda review or penalty. Consider this one of many spam signals.
Average Time on Site <40% Query Competitor Average
If your average time on site is significantly less than your competitors’ time on site, then this could be a signal for Panda to do a closer look.
Average Pages per Visit < 1.5
This is another Panda trigger. If less than 50% of your visitors bother to click another page on your site, then this may indicate your site is of lower quality, and may trigger a Panda review (of course, a review may not necessarily mean a Panda penalty). At any rate, try to improve your CTR and consider this an aggregate spam signal.
Thin Editorial Content Above 700px: Ad to text ratio above 700px > 50%
This is a Panda factor. Sites with more ads to editorial text above 700px are often pandalized. This is an aggregate spam signal.
Duplicate Design: Index page design is +90% identical to query competitors
With the advent of Google screenscraping for their SERP results, Google compares identically designed sites. Google wants quality and variety in their SERPs. How often do you see an exact match design in the same top ten? Consider this a spam signal, possibly even a Panda trigger.
Duplicate Content: Them to You +40%
Call it unfair, but our tests have found (especially in the affiliate market where Google is unsure who may be the originator) that Panda may penalize sites that have had their own content stolen (scraper sites, or thin affiliate sites, have been documented to outrank canonical sites). Having any duplicate content above 40% per page is a spam signal, even if you are the one copied. Google typically only does this in a market when their standard PageRank algorithm has been gamed enough that they lack confidence in it automatically resolving canonical issues. Protect your new content with a rel=canonical LINK Tag.
SEO Tip: Duplicate Content
What do you do if someone has stolen your content? Send them an email, a legal letter, and or a DMCA request to take it down. Failing this rewrite your content. If your content is the “authoritative” version (check in Google for a “random sentence and search for it in quotes” – the one that comes up first is usually considered the canonical version of that text) then protect it by adding a LINK tag in the header with a rel=canonical attribute.Don’t steal anyone else’s content – those pages are simply not included in the index for long. There are many cheap and good writing sources online.
Google’s SERP “Block” Option: +50% More Blocks as compared to Competitors
The advent of the “Block this Site” option in Google is the same as their invitation to “plus” a site that you found useful (and or your reluctance to do so when asked). Blocked sites will not show up for logged in users, and plussed sites will show up much more highly. Also, the “block” and “plus” have an effect to non-logged in users and too many blocks will call the Panda over, or a manual reviewer, to investigate. Consider this an aggregate spam factor.
Age less than 1 Year: New Sites are Checked More Stringently
Sadly, just having a young site puts you under a microscope. Sites under 1 year (or so) are often checked more stringently for backlinks, onpage quality, and more. Thus, consider having a new site a spam signal in itself. Our studies show that new sites only need to send some spam links their way to get penalized. This may be the work of the PageRank algorithm alone, or Panda working in conjunction with PageRank. Either way is irrelevant – consider being a new site as already having one strike against you and slowly build the safest links possible to sites under 1 year of age.
“Spunprofessional” Text: +25% Keyword Density of Bad Grammar / Typos
Matt Cuts has recently claimed that Spelling and Grammar are not part of the standard ranking algorithm, and he is likely telling the truth. However, numerous industry specialists, and other evidence, indicates that poor spelling and grammar are a part of the non-standard periodic Panda algorithim, used to detect “spun” text and unprofessional (and thus potentially low quality) sites. This check is reportedly only conducted after a bad usage metrics signal is detected. Consider bad spelling, grammar, and typos an aggregate spam factor.
Information provided by SellHealth