The document discusses several of Google's algorithms including PageRank, Penguin, Pigeon, Hummingbird, and Rank Brain. It provides brief descriptions of each:
PageRank was Google's first algorithm and measures the quantity and quality of inbound links. Penguin penalizes sites for black hat link building. Pigeon prioritizes local results. Hummingbird attempts to better understand search intent. Rank Brain closely ties to Hummingbird and uses machine learning to predict future searches.
The top three factors according to Google are links and content tied for first, followed by Rank Brain. For clients, the document recommends focusing on quality content, listings setup and audits, social media, email, and link building.