As of a few months ago you can have 3 private boards on Pinterest (a vast vast improvement in my opinion). That's where I keep my thinspo - I would get so much grief of my friends if they saw it. Hopefully the next change will be private invite only boards. I much prefer Pinterest to tumblr - too much teenage angst on tumblr for my tastes. But then there's an awful lot of wedding/über mommy boards on Pinterest! I've followed you girls who gave your addresses. XI thought I could make the Pintrest private which was why I joined pintrest but turns out I was wrong and in fact can make a tumblr private. Oh well, maybe if I have time I might change it. I'm not fussed only using is as a tool to distract myself from food. But don't know if there are any other differences.