Related comment from an HNer who worked on this at Google (from 2006 to 2010): <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=9531344" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=9531344</a>