Dropbox?  My guess is that they are trying to protect the &quot;tray login&quot; thing where the client runs without prompting you for your dropbox credentials, but that&#x27;s just a guess.<p>There&#x27;s an article about the reverse engineering of the client here: <a href="http:&#x2F;&#x2F;www.techrepublic.com&#x2F;blog&#x2F;it-security&#x2F;researchers-reverse-engineer-the-dropbox-client-what-it-means&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.techrepublic.com&#x2F;blog&#x2F;it-security&#x2F;researchers-rev...</a>