CPA is shit for Pinterest. No wonder these spammy shit messages are appearing.
What is working for me is linking pictures to useful content on a blog with Adsense strategically placed. The traffic from Pinterest can be massive and increases the chance of getting Adsense clicks.
Not making huge profits at the moment because i am still just testing with one account, but when i upscale sometime in the future i think i could make some decent income.
Just spamming hundreds of pictures in particular categories on Pinterest is so noob and is completely unnecessary. Just spending some time building up a few reputable accounts and gain interested followers is all that is needed.
Another useful method i have been testing is posting the mylikes.com offers to tumblr blogs, then pinning the picture from the tumblr blog to pinterest. This has gained me some extra clickthroughs and earned me some extra cash with mylikes.com.