A lot of webmasters have been talking about it, so I’m glad I have a chance to address it. This is something that webmaster world called “Mayday”, and it sort of happened April 28 through May 3rdish, so right around the first of May, so that’s why they’ve been calling it Mayday.
It does affect long-tailed searches more than head searches. It is deliberate, and it’s a quality change that’s been through all the normal quality launch committee, side-by-sides, making sure that things look good from a quality perspective. So, it has nothing to do with Caffeine, although Caffeine is proceeding apace, so it’s completely independent or orthogonal of Caffeine.
It is an algorithm change and so there’s no manual stuff involved here, this is purely our algorithms thinking that some sites are a better match for some queries than some other sites. And it’s not temporary. This is something where we’re trying to assess the quality of sites, we’re trying to find the best sites that match up to long-tailed queries, and it’s an algorithmic change that changes how we assess which sites are the best match for long-tailed queries.
So if you’re affected by Mayday, the sort of thing to think about is, you know, go back, ask yourself: Have I got the highest-quality site? Am I showing up for the most relevant searches? What sort of thing can I do in terms of adding great content, making sure that you know, people consider me an authority, I’m not just matching something that’s off-topic, or that users won’t find all that useful? But the main thing to know is, it is an algorithmic change, it’s gone through the full process.
There was no sort of human judgment involved with- “We thought this site was good, or we thought it was bad” instead it is algorithmic. It does affect long-tailed searches more, and after going through the entire evaluation, we did decide that it was a quality win, and so a few people have noticed it, but not the entire world has noticed it.
Bear in mind that we make over four hundred changes per year, in terms of actual quality changes where we’re tweaking, or introducing, or improving an algorithm. So, this is one of those changes. It was a little more visible to, uh, some people who really pay attention to long-tailed searches, but we do believe it’s a quality win, and we do expect it to continue going forward.
by Matt Cutts - Google's Head of Search Quality Team