thank you for taking the time to express your opinion here.

I am sure that many people download images privately on their computer, in fact that is the technical condition to view images on your computer screen.
All images are stored in the browser cache at least for some time.
Pinterest is not private it is publishing and that is the reason why so many people are interested in the service.

Your argument about image theft on the net is the well known standard. I have met enough people who think that giving a backlink is a great honour and the image owner should not only forget her copyright but should also be grateful for the traffic.

Unfortunately those sites which want to do us such generous favour are only interested to attract traffic to their little business by using other people’s work and effort for free and even without asking!

Each time an image is pinned one uploads a copy of that image to Pinterest and thatone needs to have all copyrights and licenses for publishing the image on Pinterest. At the same time one grants Pinterest a license to use that image as they say per their TOS. Should I be grateful that someone snatches my images without asking and on top of that grants rights to use the image to a third party?.

Pinterest is the first service that has based their business model on that sort of activity and if you look around on Pinterest you will see that it works in a bad way.

I am writing for my little audience and that alone will not stop the activities on Pinterest. But I hope that my post will at least make a couple of people stop,read and think, just as I did and then the news will spread. There are enough other ways to keep track of interesting things on the net.
It is not necessary to sacrifice the integrity of others for the sake of a pretty pinboard.

All I want is to retain the full right over my images, they are my property and no one should think they are free to be used or pinned etc. without asking for permission. That is all I am asking.

Added:
Even though I asked not to pin my images you pinned this blog post and a number of images from this weblog without permission. The formal DMCA to Pinterest is on the way.

Added 2 hours later: infringing content is removed by Pinterest.

Great Idea to do some research. Meantime I found pinme.org, they have a free version that does most of what one can do with Pinterest. I forgot to mention trello.com (via Seth Godin blog)
that might not be exactly what you are looking for. it is free and you can log in with a google account. The site allows you to create cards on a pinboard, you can attach images to the cards, but they will not be visible on the surface.
You can share your cards(kind of to do lists) with others,keep them private or make them public. MAin purpose is working in groups.

I closed my account on tumblr because the weblog I had was collecting nasty spam followers. Tumblr functions very much the same way as pinterest. As tumblr is publishing it is necessary that the blogger has all the copyrights required.
The material brought into tumblr becomes “their” property to some extent, especially you have to accept that other members can reblog the content on the platform. The tumblr TOS are almost identical word by word with the Pinterest TOS. Those paragraphs are almost the same on all those social media or crowd sourcing sites. Bad thing is once you have given them the material you cannot withdraw the transferred rights. You can close down your blog, but your images can still circulate.

Pinterest is driven by commercial interest from my piont of view. Sooner or later they will monetize on their users, their data and the content that they have assembled.