Pinterest: Is it a walking Copyright Infringement?

I love Pinterest.  It's a problem.  But I've wondered about the Copyright implications.  So have some other people, apparently, because there are some articles popping up about Pinterest's legal issues.

For those of you with a "Paid Content" subscription:

Pinterest: Is it a Facebook or a Grokster?

http://paidcontent.org/article/419-pinterest-is-it-a-facebook-or-a-grokster/

For a free analysis:

Is Pinterest a Haven for Copyright Infringers?

http://greekgeek.hubpages.com/hub/Is-Pinterest-a-Haven-for-Copyright-Violations

One great non-legal point that I think we need to think about is the PR fallout. Read this exceprt:

Copyright holders may also fear a public relations fallout that would come with a lawsuit. For content owners, it’s one thing to label hip-hop artists and music fans as “thieves.” But it’s quite another when the content involves food and dress pictures—even the most hardened copyright visigoth would pause at denouncing a 16-year-old who borrows pictures to make a collage of her future wedding. 

Thoughts?

Long Live Pinterest!!