The label the SEO community have given some recent Google long-tail search algorithm changes. “MayDay” because it was spotted around the 1st May 2010. Below are some attributes of this change.
- Affects long-tail searches.
- An algorithmic change rather than a crawler or indexing.
- It’s about how Google assess the best quality matches.
- Great content and authority are still valid.
- Nothing directly to do with the Caffeine update, side by side.
- Not a manual process, no humans involved, fully automated.
- Intended to be a permanent change.
Matt Cutts on the topic