Pin colors represent current behavior judged against a historical model of typical performance. Our current methodology uses the page’s HTML structure to find links and build models for them.
However, for some sites, the HTML structure changes frequently enough such that we can’t find historical models to benchmark against our current set of positions. Possible causes include dynamic ad placement, personalization, and frequent HTML template redesigns. If that's the case for your site, get in touch with us at firstname.lastname@example.org and we will set you up with a workaround.