This is a complete waste of your money. If I had the money to throw away on the Worldwide Pedophile Defense Fund, I would rather put the money aside on things I could actually use. Perhaps getting rid of one energy waster light bulb and getting an LED bulb--which would save energy and the expense of blown light bulbs. Getting a single silver dime is a good idea if you have the money to donate on the witlesses--and keep the dime. Get better quality appliances (put the money you would have donated toward upgrading something you were already going to purchase, and get better quality that lasts longer or does a better job). Or, just save it in case you need it.
This is as true with all religions. They all milk people out of money they need for themselves or could use it to improve their lives. (And, oddly, save money in the long run.) The big difference is that the witlesses proudly claim that they don't do it, then they go right ahead and do it anyways. Hypocrisy always makes the offense that much worse.