At which stage of the process does Google determine what each page is about?

The indexing stage is where Google processes the information gathered during crawling to understand the content and context of each page. This involves analyzing text, images, and other media to determine the page's topic, keywords, and overall relevance. This understanding is crucial for Google to match user queries with appropriate search results. The crawling stage is when Googlebots discover and read pages, but they don't yet interpret their meaning. The serving stage is when Google delivers search results to users, which happens after indexing. "None of these stages" is incorrect because indexing is precisely where this determination occurs.