Stats published this week by Searchmetrics in the wake of the latest major update to Google’s Penguin algorithm have ranked the sites that have been most impacted by the roll-out and there are clearly some lessons to be learned from these figures.

The SEO visibility of many sites has been seriously hampered according to the report, which shows that major organisations like the Salvation Army were hit by Penguin.

It was not just big sites that took a hit, but also a number of smaller sites operated by businesses, according to Searchmetrics spokesperson Marcus Tober.

He said that the data suggests it was thin sites which bore the brunt of the algorithm’s wrath, with untrustworthy and irrelevant links causing damage to the search rank of various businesses.

Tober argued that webmasters who did not fully appreciate the importance of SEO were now feeling the sting of their unpreparedness coming back to bite them.

In the worst cases sites saw their visibility decrease by almost 60%, which could be seriously problematic for any company which relies on web traffic to generate revenue.

Of course there are some things to bear in mind when looking at the results posted by Searchmetrics, since this kind of analysis may be revealing trends that are not entirely down to the influence of the latest Penguin update.

Google’s interminable tweaking of its algorithms can cause quite big shifts for certain sites irrespective of whether or not a major release has just occurred. In fact the search giant has actually been attempting to integrate a more seamless degree of evolution and continuity to its updates so that they occur incrementally rather than in one big dump.

This rolling approach does mean that ranks can change with a greater degree of regularity than they might have in the past, so it is necessary to consider these stats from Searchmetrics as a useful way to measure ongoing alterations without necessarily counting them as a gospel interpretation of Penguin’s impact.

What is undeniably true is Tober’s assertion about the importance of SEO and how complacency towards it can result in search ranking disasters irrespective of whether or not Google has been meddling with its underlying algorithms.

Thin and irrelevant links, like thin and irrelevant content, can be fatal for sites of all sizes, which means companies need to work hard to constantly monitor and improve the quality of a site so that it is naturally going to be in Google’s good books and ascend the search ranks without the need for underhanded tactics that deliver short term boosts which are not sustainable.

The biggest threat to your site’s rank is not from competitors, but is in fact internal laziness and the assumption that doing the bare minimum for SEO will be good enough. This is something that needs constant work and refinement, just as Google feels its search engine should be perpetually updated.

Now is the time to act if you think your site could do with some SEO improvements.