What's the deal with significantLinks?

[NerdsOnCall]

http://schema.org/significantLink

Schema.org has a definition for "non-navigation links that are clicked on the most." Presumably this means something like the big green buttons on Moz's homepage. But does anyone know how they affect anything?

In http://moz.com/blog/schemaorg-a-new-approach-to-structured-data-for-seo#comment-142936, Jeremy Nelson says " It's quite possible that significant links will pass anchor text as well if a previous link to the page was set in navigation, effictively making obselete the first-link-counts rule, and I am interested in putting that to test." This is a pretty obscure comment but it's one of the only results I could find on the subject. Is this BS? I can't even make out what all of it is saying.

So what's the deal with significantLinks and how can we use them to SEO?