The problem is maybe that people _think_ it is safe to send &quot;personal&quot; messages.<p>No one would send personal information through Facebook public posts, but if Facebook has a &quot;private&quot; or &quot;group&quot; setting then people will trust that thing is really not being seen by anybody.<p>I don&#x27;t use Facebook or WhatsApp to not encourage these stupidities, but some other day a friend told me she was very annoyed by the fact that advertisign suddenly began to appear on Facebook about a topic she had just mentioned in a &quot;private&quot; chat conversation.