Ha! Delete them.
It's evolved now into facebook statuses. 'Copy and paste this into your status or you'll have bad luck!' I'm not kidding, there was one that suggested unless you posted it, bad luck would follow you around, with a reference to feng shui.
The worst ones are the 'copy this into your status if you support the troops/dislike homelessness/hate child abuse'. Hey, you know what would be way more effective at combatting general issues? Actually donating to a charity or organisation, or giving your time. It doesn't raise awareness really does it, to post saying 'copy this if someone you know died of breast cancer'. Everyone knows about breast cancer and that it exists - it'd be far more valuable to do the race for life or something.