Great review of Pinterest and why it's becoming so popular here: What is Pinterest?
If you haven't heard of it yet, Pinterest is a new social network (yes, another one!) where you "pin" photos you like to your board. It is a very visually compelling site that plays to the internet's love of pictures. From a public relations and marketing perspective, it should motivate you to use more creative imagery on your website, especially in your blog posts, giving your posts more of a chance to be pinned in Pinterest and discovered by more people. Another benefit is that when something is pinned, a backlink is pinned along with it to your website. Pinterest has a page rank of six which gives that "follow" backlink a lot of juice when it comes to improving your results in the search engines!