Pinterest, the social media website founded by West Des Moines native Ben Silbermann, announced late last week that it will begin experimenting with promotional posts from businesses. Silbermann, in a letter that was mass emailed to users, said the promoted posts wouldn't be banner ads, and promised they would be tasteful, transparent and relevant. The site will start out by posting a few pins in search results and category feeds, he said. "Nobody's paying for anything, yet - we want to see how things go and, more than anything, hear what you think," he said. Read this TechCrunch article for more information.