Pinterest had been beta testing their "Promoted Pins" advertising product and found some great success with it. They now plan to roll this out to all of their partners at the start of 2015.

http://marketingland.com/promoted-pins-set-make-debut-partners-early-data-shows-suprisingly-effective-results-112631

It was found that organic pins get repinned an average of 11 times, and promoted pins performed just as well, if not better. From my experience, I can believe this statisic because I often don't even realize I'm repinning a Promoted Pin until after the fact. They are not very intrusive, in my opinion.