When we talk about how web sites are related, it’s not unusual for us to talk about links between sites and pages. Google pays a lot of attention between such links, and they are at the heart of one of its most well known ranking signal – PageRank. PageRank is now more than 15 years old, predating the origin of Google itself in the BackRub search engine.
Google is exploring other signals that may be used to rank pages in search results, including social signals that may result in reputation scores for authors, in relationships between words that might appear together on pages ranking for the same queries, and in relationships between pages that show up in the same search results and in the same search sessions. The Google paper presented at an October 2013 natural language processing conference, Open-Domain Fine-Grained Class Extraction from Web Search Queries (pdf), provides some interesting hints at a possible Google of the future.
Google also seems to be very interested in building a knowledge base of concepts that better understands things like what different businesses or entities are ‘Known for’ or by defining entities better in ‘is a’ relationships. Sometimes pages for specific entities show up at the top of search results because they seem to be the page that people are looking for when they include that entity within a query, like the first two results on a search for [Roald Dahl], as seen in the image below: