Pinterest is a new and quickly evolving entity. Basically an infant social networking site trying to find its place in the world. One of its biggest challenges is dealing with copyright issues and finding a way to make money.
Currently it is making money via affiliate links. For example if you post a photo of the Nikon D800 under your "I gotta have" board, Pinterest adds a link to Amazon.com and if someone buys it via the link, they make a commission.
Recently Pinterest updated their terms specifically clarifying the notion that they could sell the images posted and addressing the copyright infringement issue:
"Our original Terms stated that by posting content to Pinterest you grant Pinterest the right for to sell your content. Selling content was never our intention and we removed this from our updated Terms."
"We released simpler tools for anyone to report alleged copyright or trademark infringements."
Right now Pinterest might be used to attract attention to your portfolio but the users are unlikely to be buyers of microstock although certainly there are a lot of home bloggers.
As someone suggested recently on message boards, the link of DT images on Pinterest probably would be best linking to Timelineimages because that would better match the user base.
Also other companies have worked out deals with Pinterest so that their links to their images are UNEDITABLE. This would make sense for DT to peruse such a relationship with with Pinterest.
Of course this doesn't stop this scenario. Someone buys the rights to a DT image, posts it on their blog and then pins it. Now that image on Pinterest links to the blog. But this isn't anything new. Once your image is posted on a blog or website its pretty much out there.