Personally I have a Pinry board that I host privately amongst my company, we all post images/inspiration for sites/ui we find around the web and it's all password protected. Copyrighted content isn't an issue cause only 4 of us ever see it.

But this is the same question you should have for a Blog I'd think, if you host copyrighted content on a blog then you'll have the same issues if it's a public blog.