The authuser=0 parameter tells Google which signed-in account to use. If you have multiple Google accounts logged in (e.g., personal and work), authuser=0 means .

The parameter authuser=0 is a standard Google technical indicator that you are viewing the profile for the first (default) Google account currently signed into your browser. Purpose and Functionality

We sampled 200 search results across five query categories (product queries, local services, news topics, academic queries, and creator/author searches). For each result we recorded presence of profile links, author snippets, rich results, and structured metadata (schema.org author, publication date).