Windows only: Online payment service PayPal rolled out a service a few months back that lets you generate and use single-use credit cards in order to make PayPal payments at sites you might not want to give your credit card information to. The PayPal Plug-In, for Internet Explorer 7 and (at the moment) Firefox 2, makes using "Secure Cards" much easier. When you're at a site you want to pay with, you can create a card, fill a payment form with the card's details, and even check your PayPal balance, all from a drop-down menu. For regular auction buyers or those venturing into unfamiliar web territory, it could be convenient peace of mind. The PayPal Plug-In is a free download for Windows systems only.
PayPal Plug-In [via Download Squad]