2013 Updates
Penguin 2.1 (#5) — October 4, 2013
After a 4-1/2 month gap, Google launched another Penguin update. Given the 2.1 designation, this was probably a data update (primarily) and not a major change to the Penguin algorithm. The overall impact seemed to be moderate, although some webmasters reported being hit hard.
Penguin 5, With The Penguin 2.1 Spam-Filtering Algorithm, Is Now Live (SEL)
Google Penguin 2.1 Was A Big Hit (SER)
Hummingbird — August 20, 2013
Announced on September 26th, Google suggested that the "Hummingbird" update rolled out about a month earlier. Our best guess ties it to a MozCast spike on August 20th and many reports of flux from August 20-22. Hummingbird has been compared to Caffeine, and seems to be a core algorithm update that may power...