I have a business account with Pinterest, so I'm one of those that pays for promoted pins that so many complain about. I set up who I'd like to target and I honestly try to target only people that might be interested in my product. That said, when I look at the promoted pins or suggested pins that Pinterest sends me, easily 9 out of 10 have absolutely nothing to do with my interests, the pins I look at, like or save. I sell custom furniture. When I go to look at my own pins and then look at the pins they put withbthem as "more like this" I can't for the life of me figure out what sort of algorithm they use to match these. Pinterest could be very beneficial for a small business like mine but I've stopped using it because I feel like their targeting is just a joke. If you have a question and try to get in touch with their support team, it takes two or three days to get any kind of a response and again 9 out of 10 times they'll totally ignore the question I asked and refer me to their helps page. I've just given up.