Do you use your credit card for online purchases ?

[rjruby]

I use one-shot numbers.

My 3 cc companies allow me to 'make-up' one-use credit card numbers, good for as long as I say with a specific credit limit.

They won't work for recurring charges but are great for that one-time purchase.

Do they provide you with a 3 digit security number that is normally on the reverse side of the redit card and is usually required my some merchants?