
1. Panda
Launch date: February 24, 2011
Hazards: Duplicate, plagiarized or thin content; user-generated spam; keyword stuffing
How it works: Panda assigns a so-called “quality score” to web pages; this score is then used as a ranking factor. Initially, Panda was a filter rather than part of Google’s ranking algo, but in January 2016, it was officially incorporated into the core algorithm. Panda rollouts have become more frequent, so both penalties...