This is the unique ID for your site in Piwik PRO. <a href="https://help.piwik.pro/support/questions/find-website-id/" target="_blank">Where to find it?</a><br /><br />
<strong>Note:</strong> If you’re using WordPress <strong>Classic Theme</strong> make sure it has the <code>wp_body_open()</code><br />
function right after the opening <code><body></code> tag, otherwise the container won’t work.