<i>&gt; It would hose only your &quot;usermode&quot; apps, which would be a small subset</i><p>Until more and more user apps start to get out of sync with the &quot;system&quot; versions of things, and therefore need to be installed with the &quot;user&quot; option in order to work.<p><i>&gt; What hack would rely on some specific app being deployed in user-mode anyway?</i><p>A hack that doesn&#x27;t care about specific apps but just wants to compromise whatever it can. Like, you know, a virus.<p><i>&gt; To do what, steal user files it already has access to?</i><p>And send them to the Internet, without your knowledge. Like viruses already do--only it&#x27;s a lot harder to get them to run on Linux. At least, it is now.