Using microdata markup such as this on Dani's profile page with URL http://www.example.com/dani.html
<body itemscope itemtype="http://schema.org/ProfilePage">
<h1 itemprop="name">About Dani</h1>
<div itemscope itemprop="about" itemtype="http://schema.org/Person">
<link itemprop="url" href="http://www.example.com/dani.html" />
</div>
</body>
Is it appropriate to set the URL element to the ProfilePage item or the URL element for the Person item to http://www.example.com/dani.html? From what I understand, the URL is used as the unique identifier ID?