I've seen too many administrators show up to a faculty meeting excited about sharing some interesting resources they've found, using an email to themselves full of links and they have a really hard time remembering which link goes to which resource, and have a hard time remembering which link they've already clicked after selecting a few.
It's frustrating for the audience and tense for the administrator because it kills their excitement and the attention of teachers who've spent all day trying to keep the attention of lot of students. Using Pinterest is one way to display interesting 'stuff' that an administrator finds on the Internet. They can easily display images, video, and other links around the web.
There's no need trying to remember which link (and we know some of them are very long) goes to which resource because each 'Pin' has its own thumbnail that helps viewers understand what the Pin is about. Also, with the opportunity to arrange Pins in the order the administrator would like, they can make the most important or impactful Pin at the top.