Legal problems from posting on Pinterest?

It's not infringement cause it's fair use, if you use it the way it's set up to be used. How is it any different than Google Images? Google pulls up images from all sorts of sites and displays them on GOOGLE's website, with a link to the site hosting the image. Pinterest is exactly the same thing, except that it is manual and user voted what to display. When you add a pin to their site they will only scan for images of the URL that you type in, and so then the image is linked to the source page of the image, EXACTLY as it is on Google Images. So Pinterest has built in attribution through this linking system. Also, people posting images on Pinterest are mainly doing so in the spirit and purpose of commentary and not for commercial purposes that are against the benefit of the source.

I would not worry about it at all. There are millions of blogs out there that use other people's photos from commercial sites, celebrities etc. and they are not getting mass cease and desist letters. Which is what they would get before any company or person took further legal action against them. All these blogs are relying on the fair use law, since they are using the photos in commentary or news and commenting their opinions on them or whatever. It's the same with Pinterest, and even better cause they are linked to the source giving the people that published the photos FREE valuable traffic. It's free viral advertising for their sites and products. Why in the world would they be upset about that? On the contrary, more and more sites and companies will be adding Pin It buttons to their sites, just like they have 'Share' this on Facebook or Twitter etc. How is it any less fair use than sharing a story/link on a Facebook wall, when Facebook automatically captures and posts a small preview photo of the page on the Facebook wall along with the link? No one will be upset about free advertising.

On the other hand, some people could abuse that just like they could in any medium like Facebook, YouTube or their own site or blog. If they were to upload others copywritted photos and then had a link to a totally unrelated commercial site or product, that would no longer be fair use! So of course Pinterest is going to have to protect themselves with those terms, and it's the same terms Facebook or YouTube or any other social media site has. Though Pinterest makes it more difficult for people to do anything like that since they will only extract photos from the actual link submitted. If you upload a photo from your computer then you can't add a link. Though if someone was using Pinterest to link to copywrited photos they put on their own blog that they are using in a non legal fair use way, then it's only fair the liability is on them.

"First and foremost, courts have found that to be "fair" a use has to be transformative and not just reproductive. This means that someone cannot simply start up a blog and upload all the images from the Neiman Marcus website. This would be a merely reproductive use that was not in any way transformative. If, however, you upload select photos from the Neiman Marcus website in order to comment on or criticize the store, products, or even the photograph itself, you are not longer just reproducing the work, you are transforming it. If you are using an image for the following purposes, it is most likely a transformative fair use and not copyright infringement: criticism, comment, news reporting; teaching; scholarship or research; parody."

So I would be careful about which photos you use on your own sites that link to or are for the purpose of linking to a non-related affiliate link that has nothing to do with the photo or it's source, regardless of weather you pin it on Pinterest or where you link to it.