Ted is not correct. Their acceptable use policy is irrelevant, in terms of whether or not something is spam. the method of how a repin is made or how a new pin is put up may not be acceptable to Pinterest but that does not make it spam (spam is an unsolicited message).
On the spam issue if it helps you understand what spam is try googling: A definition of Spam
If it helps here is the free dict url http://www.thefreedictionary.com/Spam you can ignore the references to canned food!
So coming back to their acceptable use policy seeing how you wish to derail this thread:
Do you think an organisations terms and conditions or TOS are always ethical, moral, or within "fair use"?
It is up to us as individuals to decide if we are overstepping the mark when refusing any of these. Its a good job Microsoft, broke from ethics when they allegedly and arguably stole IBM's core new OS which they decided to call Windows. The ultimate hypocrites who respect nobody else's ethics, TOS or even European law.
Of course some organisations are reasonable. What's important is that we are the guardian's of our own actions and choices to infringe or break contract with each other or with organisations. When these breeches are beyond the law obviously there is a potential cost.
So please shyflower let myself and the governance of Pinterest have our debate over what is "fair use", about the differences between legitimate automation and automation for the sake of spam, and then we can fight about whose jurisdiction we are in.
Thanks for your contribution!