I'd love to use Pinterest. But if I can't use it in conjunction with Flickr, then why bother?
I'm a hackerspace-goer, and at my Hackerspace (Albuquerquites, check out Quelab) we have a camera with an EyeFi card in it that auto-uploads to Flickr.
The photos are licensed CC/BA. Pinning them would violate the attribution, since I can't say "it came from x"
This keeps me from keeping a log/journal using Pinterest of my various adventures.
The easy solution to the problem Pinterest now has isn't blocking, but to tag each item that is pinned with the source it came from -- much like Tumblr does.