Is Yahoo! Shopping secure?
Yes. Yahoo! Shopping uses secure servers to protect your personal information, including your name, address, and credit card information. We use the Stronghold secure server, currently the second-best selling secure server software and, in our opinion, the best product technically. It supports industry-standard 128-bit SSL encryption. When you enter your credit card number into the order form, it is transmitted across the Internet in an encrypted (scrambled) form and not decoded until we receive it. For added security, we also encrypt the credit card number when it is stored on disk and when we forward it to the merchant.

Shopping online is considered fairly low-risk. According to CNN, "The prevalent opinion... is that online credit card use is actually no riskier for consumers than traditional 'low-tech' transactions." You should feel as safe as you would using a credit card in a store or restaurant, if not more so.