Some of the suggestions for libraries:
"What could a library do with Pinterest?
• Use it to drive traffic to your website and online collections
• Use it to promote image collections (copyright permitting) like the New York Public Library Picture of the Day pinboard
• Use it to promote children's programming and offer alternative craft ideas for at home use
• Collect images that relate to your local studies area like the Chicago History Museum pinboard
• Hold a class to show library clients how to explore and use Pinterest for themselves..."
Via Karen du Toit