Two weeks ago, Google rolled out changes to its algorithm in an attempt to decrease visibility and rankings of low quality sites on 11.8% of search queries, called the Panda Update. “Low quality” is defined on search engine blogs  as content that is shallow or limited, poorly written, copied, and generally not useful to users.

I don’t know about the rest of you, but whenever a big Google update rolls out, I’m back in elementary school gingerly turning in a pop quiz – I think that I’ve paid attention in class, but in that moment, all I can do is lace my fingers behind my back and wait patiently for the teacher to grade my work.

In addition to the SEO benefits of fresh user-generated content (UGC) on product pages, we have seen time and time again that UGC aggregated into branded archive-like pages can attract a substantial amount of ridiculous long tail keyword traffic. As the Panda Update was announced, we knew that UGC Archive sites would be affected in some way. With a bit of cautious uncertainty in mind, we randomly selected a group of archive sites and started monitoring.

The UGC Archive sites we used in this study include a very basic navigational link structure that follows the company’s category hierarchy. At the deepest level, product UGC pages have minimal product details and are dominated with user language – typically 20 Reviews or Q&A per page. Because these archive sites are typically isolated from other marketing initiatives, and have very few backlinks, they created a very pure sample with which we could evaluate how the Panda Update reacted to UGC.

The sample included 10 U.S. Archive sites in various industries (general retail, specialty retail, electronics manufacturing, beauty manufacturing, and entertainment) for two types of UGC – reviews and Q&A. The sites have a wide range of UGC volume – some literally have millions of pieces of content, and some have tens of thousands. To isolate the impact of the Panda Update on Google organic visits, we compared the two weeks since the update against the two weeks immediately prior, and then compared those to the same weeks last year.

After a day or so of nail biting, the Panda Update pop quiz came back remarkably well:

Based on this graph, we can see that:

• In 2010, this span of weeks was fairly flat – for 8 of these 10 sites, traffic fluctuated by less than 10% up or down (two sites were on a pretty steep upward trajectory).
• However, in 2011, 6 of the 10 sites increased by over 10% after the Panda Update and all of them increased at least somewhat (none dropped).

We wondered if all of this traffic was coming from more keywords or simply higher SERP rankings, so we analyzed how the number of keywords had fluctuated during the same periods outlined above:

From this data, the results are still pretty clear – in 2011, for 8 out of 10 sites, there was a higher increase number of keywords in the weeks after the Panda Update than there were the previous year. We already knew Google values UGC; with this data, we now know Google values aggregated UGC.

As for Google Webmaster Tools data, impressions increased recently for all of the sites between 39-84%; clicks dropped slightly for a couple of sites but increased by 10-15% for most sites; CTRs increased modestly for all sites. The most interesting data point I found in Webmaster Tools was average position – four of the sites actually dropped in average position, but those same sites had the highest increased impressions. It makes sense that when Google introduces new sites to replace old ones, it could drag down the overall average position in SERPs for the new sites.

User-generated content, while sometimes only one sentence individually, aggregated together can be very powerful for an SEO campaign. Customers convert higher when they see authentic content from like-minded users, driving Google to gravitate towards pages with legitimate UGC. To get the greatest value out of UGC for SEO, inject a small amount of the most recent UGC into product pages to increase richness and freshness; however, also make sure to have a branded interactive archive that allows Google to fully index all UGC for each of your products. With the Panda Update, Google impacted 11.8% of search queries.  Once again, UGC proved to be a vital asset as these sites are reaping the benefits of the algorithm change.