Amusingly hidden behind a paywall as usual (ironic considering that Nature bases its content and profit on the free labour of others, including the reviewers), there's a letter suggesting peer reviewers should be paid. I've found this idea a handy way of turning down reviewing invitations that I'm not really that desperate to do, without appearing too rude or selfish. "Please Dr Esteemed Scientist, we would greatly value your expertise in reviewing this manuscript." "Yes, of course I'd be happy to review it, and my fee will be £X." "Oh, we don't really think your input is valuable after all. " Kthxbye.