Information that Facebook users designate as private through their privacy settings will not be made available for indexing by search engines regardless of whether the 'Allow indexing' option is enabled or disabled
Facebook doesn't have an easy-to-use advanced search engine, so one guy built his own.
Private browsing using the supposedly private or incognito modes on your regular browser does not give you the level of privacy you think it does.
Best Search Engines That Respect Your Privacy - BestVPN.com.
There are certain web pages on Facebook, mainly the Facebook Email Opt Out web page, that are getting indexed by the search engines.
About 2 weeks ago, Facebook’s “new and improved” privacy settings were announced. When you click next you get a screen to update your privacy settings (see image below). Many of the defaults on this page are to open your profile information to “everyone“, which includes search engines – and Google.
Moreover, this private search engine also protects your privacy from advertisers, though it may show some ads.
My secret account is now not so private after Facebook updated its search engine without warning, and there’s nothing I can do about it.
“The ability to search for a person by phone number is intentional behavior and not a bug in Facebook. By default, your privacy settings allow everyone to find you
Introducing its new search engine, Facebook assured users that the system is strongly privacy aware.