Pinterest has its own regulations with regards to copyright and trademark infringements. Complaints may be filed against moodboards and images which are misleading or form an infringement on copyright or trademark rights. However, Pinterest determines whether or not there is an actual infringement or not (as is usual with social media). Transfer or sale of a Pinterest account is not possible, only when Pinterest acts as an intermediate. Since an ounce of prevention is worth a pound of cure, e kindly advise you to register your Pinterest account timely, for e-commerce reasons, as well for prevention of trademark conflicts.