Adding special markup or text to user profile page

Create a theme component and add something like this in your Common > Head tab

<script type="text/x-handlebars" data-template-name="/connectors/above-user-preferences/foobar">
  <div class=mainsite>
    <h3>This is your forum profile. If you want to change your user profile,  <a href="YOUR-SITE-URL">go here</a></h3>
  </div>
</script>

Then you can customize it as you prefer from the Common > CSS tab

.mainsite {
    background: #d1f0ff;
    padding: 4px 10px;
}

change YOUR-SITE-URL with the url you prefer and the result will be something like this when a user enter his preferences page