Social networks know that no one wants adverts all up in their feed --it's no wonder they try to sugar coat paid-for posts. Twitter sneaks in "promoted" tweets; Facebook has its "sponsored" posts; and soon you can expect "Promoted Pins" from -- where else? -- Pinterest. The program has been running in beta for a while, but starting January 1st, it's open to all advertisers. What does this mean for you, dear Pinner? Well, we imagine a few more pictures of brand name lattes mixed in with all the photos of rosetta'd lattes. With around 70 million users, the picture-based network might not have the numbers of Twitter or Facebook, but it does have the advantage that many are already using the site to collect and search for things they want. Pinterest is also launching a program called "The Pinstitute" to teach advertisers how to better connect with (and be less annoying to) its users. In reality, it sounds more like analytics and feedback, but anything that might prevent your meticulously curated boards from being soiled with bad branding is fine with us.