I have tried to do this before. (Manually, but still.)

It does not work. People genuinely want to buy you useless junk you don't actually want.

This is kind of true. If you stick with it people eventually come around. I've been doing it for years. Dig it:

http://www.petermichaud.com/essays/new-rules-for-christmas/

I've tried it too, although I've said to donate to a charity of their choice in my name. In retrospect, I wonder if making them choose made them more or less likely to give...

I would like to try it, but to be honest I haven't figured out how to do it without coming across as... sanctimonious?

"... your favorite charity"

Tried to sign up because I want to do this. But there are only 7 charities to choose from, none of which are my favorite

Sorry, but I'm not giving my credit card information to any website that allows me to authenticate through facebook.

You can opt to create a swipegood.com account instead of connecting via facebook.

I did see that, but the fact that facebook is even an option just put me off straight away.

Understandable. But frankly, if you've ever seen how banks operate their technical infrastructure you'd want to store all your money in a matress. I'm confident Facebook has much smarter people working to make sure their products are secure.

Most banks have ssl encrypted sites.

I think that's a bit unfair. Many large properties allow authentication through Facebook. I don't see why there is a concern with credit card information and Facebook authentication?

I like facebook log-in. No separate credentials to keep track of.

Honestly, if it was up to me (and I didn't have any kids) I would probably just skip Christmas entirely, save the part about eating a bunch of nice food. Spending a bunch of money on family that I only see at Christmas (purposely) and chopping down a perfectly good tree, dancing around it singing songs in honor of a nonexistent diety whose supports have murdered people I respect by burning them on the stake is just not my idea of a great time.