Google Keeps Tweaking Its Search Engine

Mr. Singhal is the master of what Google calls its “ranking algorithm” — the formulas that decide which Web pages best answer each user’s question. It is a crucial part of Google’s inner sanctum, a department called “search quality” that the company treats like a state secret. Google rarely allows outsiders to visit the unit, and it has been cautious about allowing Mr. Singhal to speak with the news media…