After seeing many public mentions of Google's May "MayDay" update, I was surprised to see that the June update received almost no public discussion.
MayDay didn't affect my sites in any noticeable way, but the June update had immediately noticeable and significant effects. About 80% of my approximately 1,300 EMD's and many of my medium (50-500 page) sites lost their rankings in the update.
Interestingly, this did not have a significant impact on revenue. The affected sites were mostly poor earners to begin with. This update will effect revenue projections for 2011+, when those sites were supposed to really start performing.
At first, it looked like Google had changed, or even removed, the massive bonus it gives to exact match domains with com, net, and org extensions.
I was convinced out of that theory because some of my .biz and .us domains were also affected by the update, and because the content pages of many of my newer medium sites were also affected. Nonetheless, EMD's did get hit pretty hard and they provide a wonderful test bed for examining this update.
The medium sites that lost their rankings included DearTips, HowToPlant, TheShould, WhatCauses, and WhatPain.
One interesting example of how strange this update was is that HowToPlant got hammered in this update, while GrowGuides was untouched. The two sites are almost clones of each other, although both have unique content. They chase almost the same keywords and they were promoted almost exactly the same.
Raw PageRank didn't seem to protect sites from the June update. I had many PR3 EMD's lose their ranking in this update.
Page count also did not seem to help. Many of the one page EMD's were not affected, while some of the EMD's with 10+ pages were affected.
Thus far I can find no real differences between the sites that were affected and the sites that were not affected. Fexofenadine was dropped from #2 all the way out of the top fifty, but Dicyclomine was untouched. Those sites are almost clones of each other.
Another example of the apparent randomness of this update is that StrawberryShortcakeRecipe was unaffected, while hundreds of sites extremely similar to it were removed from the SERPs. I do not see any significant difference between that site and many sites that are no longer in the SERPs.
The strangest thing I am seeing is that the EMD's I built and then never promoted are doing better than the EMD's I built and then promoted lightly. The EMD's which I built and then promoted heavily are doing the best. I can't exactly define "lightly" and "heavily", but it does seem to point to "you need more than article marketing links now."
My current theory is that this is some sort of over-optimization penalty. If there is an over-optimization penalty, I have been begging to get hit. I have been using very little anchor text diversity in my link building efforts.
This also might be related to insufficient linkdomain diversity, as a large portion of my inbound links come from article marketing.
We built a large number of new links using article marketing, but with variant anchor text. This appears to have had zero effect.
We built a large number of new directory links to a few of the sites. This appears to have had zero effect.
We built a large number of new profile links to one of the sites. This appears to have had zero effect, but it's too soon to be certain.
We're build a large number of new links using article marketing, but pointing to the article URL instead of to the index URL. It is too soon to see if this has any effect.
We need to de-optimize the on-page SEO of a group of our EMDs and watch the results.
One of my coopetitors has been adding lots of new pages to his EMD's and building links to those pages. That's been getting his index pages back into the SERPS. I'm not sure that I want to do this, as the RoI may not support the additional investment. But... I do have to do a few to test.