Google's Testing A Self-Improving Ranking Algorithm? (MayDay)

May 14, 2010 • 8:23 am | comments (7) by twitter Google+ | Filed Under Google Search Engine Optimization

Early May we reported on a possible Google Update coined the Google MayDay update. Now, I know Google wanted examples of sites claiming they were hit, so here you go, SEOmoz said they were impacted by MayDay.

What is MayDay, well - a lot of sites are claiming they lost rankings in Google for their long tail keywords, which resulted in a drop of traffic of about 10 - 20% or more. Now, with the launch of new Google design some are blaming that for a Google referrer drop but some noticed it before the redesign.

A new WebmasterWorldthread started on the topic, the second one on this topic. We have some smart SEOs and webmasters formulating ideas and theories, some of you who may disagree with them, but I will document them here anyway.

Tedster believes that what we are witnessing over at Google now may be a "automated, and self-improving algorithm" deployed by Google. Possibly part of how Google indexes content with "un-launched" Google Caffeine update. He explains:

There is a lot going on with Google and we may need to approach the Google SERPs from an entirely different model than the "data set" concept that we've been using in recent times. I'm currently thinking of something more along the lines of waveforms and continuous statistical testing... with near-real-time adjustments and experimentation in a kind of feedback loop. Something like automated algorithm evolution.

Rand from SEOmoz also formulated some theories, which he posted in his video.

I really think Google needs to do a blog post about what is going on or not going on soon. Between Caffeine, the new design and this - there is just so much confusion out there. Today's Google should not be like this, their communication has been outstanding but when it comes to this topic - it is like they are hiding something.

Forum discussion at WebmasterWorld. Update: After this post, a bunch of us at Search Engine Land decided to get Google on the record on the May Day update. We got them to confirm this is a change to the ranking algorithm and not a change to indexing or crawling. Vanessa Fox wrote it up and goes into more detail there. Here is a quote:

Last week at Google I/O, I was on a panel with Googler Matt Cutts who said, when asked during Q&A, ”this is an algorithmic change in Google, looking for higher quality sites to surface for long tail queries. It went through vigorous testing and isn’t going to be rolled back.”

I asked Google for more specifics and they told me that it was a rankings change, not a crawling or indexing change, which seems to imply that sites getting less traffic still have their pages indexed, but some of those pages are no longer ranking as highly as before. Based on Matt’s comment, this change impacts “long tail” traffic, which generally is from longer queries that few people search for individually, but in aggregate can provide a large percentage of traffic.

Update 2: Matt Cutts of Google posted a video on this topic, watch the May Day Video on our blog.

Previous story: Removing URLs in XML Sitemap Won't Hurt Your Google Rankings


Michael Martinez

05/14/2010 04:17 pm

I can't really see a whole lot of change in my Google traffic but I'm getting substantially more traffic from Bing. Naturally, no one in the SEO community is looking at that. :) One thing I have noticed is that Google appears to be showing completely different results sets on a random basis. Maybe this is what people are noticing in their referral losses. And perhaps it's just a congruence of several factors/events. I suspect this is the most likely explanation.

Stuart Livesey

05/14/2010 07:37 pm

While Google traffic seems to be up across a number of our clients' sites it's the traffic from Bing that looks to be more productive.


05/15/2010 12:00 pm

I don't see that much effect.. But for some weird reason I get much more traffic from Yahoo!, Bing.. And even Bauido or what ever it called..

Neva Howell

05/16/2010 01:17 pm

I noticed a SIGNIFICANT drop in searches for my most important health-related terms. I knew something was going it but, like mercury retrograde, I didn't find out what for another week. May Day has definitely hurt my business and, also, for the record, I don't get as relevant sites coming up in my own searches on google as I did before. I use longtail searches to find very specific health information and now, it's harder to find.


05/17/2010 04:43 pm

I have seen huge decreses in indexed pages along with many other competitors, decreases in traffic average about 15-30% in my industry. It all started over a month ago.

Eric G

05/18/2010 03:56 pm

Michael above is correct. Google Datacenters have been showing "old" results and different result at periodic junctions as they perform enhancements. I have been tracking this phenomenon for over a year and a half. SERP results would display data that appeared to be months old. Sites that didn't rank currently would be right back at the top etc. This retro data would be displayed for a day or two, then a another set of Older data would be displayed. When tracking specific keywords for a long period of time and I was able to pin point the exact results from prior dates. About a week or so of "Retro Data" then a Google Improvement would be displayed. I assumed Google was testing their enhancements with various data sets. This has happened at least 4 times in the past year and a half. This type of retro data being displayed across the Google datacenters would account for a decrease in traffic especially if the keyword terms were ranking poorly in the past.


09/13/2010 01:04 am

From my observation, they are constantly rotating long tail results. I see it day in day out, and i believe they're using the feedback from these results to slowly build up a new set of rankings. I think this will take a while, which is why we're seeing fluctuations.

blog comments powered by Disqus