Via Hacker News, I came across a Tweet implying that Facebook's iOS app routinely reads and transmits all content from the user's pasteboard.
Leaving aside whether Facebook's app genuinely does this (which is a separate question), is this possible? I had always naively assumed that an app couldn't access what was on my clipboard unless I explicitly chose to "Paste" into a native text view. Is that assumption wrong? What is the security model for the content of the clipboard on the two major phone OSes? (Or what are the security models, if it's handled differently between iOS and Android?)