This reminds me of the old concept of &quot;tab damage&quot;[1] on usenet&#x2F;mailing lists. People used to leave little &quot;devices&quot; in their signatures that based on this that would point to the number of times a message had been forwarded or quoted, because client software would typically indent the quoted message.<p>[1] <a href="http:&#x2F;&#x2F;linuxmafia.com&#x2F;~rick&#x2F;afw&#x2F;#tabdamage" rel="nofollow">http:&#x2F;&#x2F;linuxmafia.com&#x2F;~rick&#x2F;afw&#x2F;#tabdamage</a>