The Copyright Zone reports on a trend in attorney's continuing education to offer classes aimed at defending clients against cases of copyright infringement. The second point is worth noting:
2. Send a letter saying “We have taken it down. Thanks for letting us know. Goodnight”. Never offer real money to a non-represented claimant. Few photographers hire lawyers. If you do hear from a lawyer then you can start paying real attention to the case.
Pinners will love point #5:
5. Always claim that since there was no copyright notice your client who is not a lawyer, “had no reason to know anything was wrong” and that “no malice was intended”.