[adventured]

Their SEO was/is technically extremely poor (per Google's rules) and should have gotten their content largely banished from Google. They were intentionally violating one of Google search's primary SEO rules: do not show the Google bot and users a meaningfully different site. Quora was doing exactly that, providing a very different experience to the non-signed in search user (arriving to the site via search results) vs Google bot. Google let Quora get away with SEO murder (speculation on HN has always been that it was due to the close relationships in SV), which is the sole thing that has kept Quora propped up (otherwise its traffic would have been properly obliterated for its blackhat SEO practices).