Using secure socket layer, or SSL, technology, late-model browsers can encrypt information as it leaves your computer, making it nearly impossible for anyone other than the intended recipient to decrypt it. Just like sending any other data over the Internet, others can still capture your encrypted information, but what they see is so much gobbledygook that it would take them centuries to decipher it.

SSL requires additional processing time on both the sending and receiving ends (in other words, it makes pages load even more slowly than normal), so it's typically used only on pages where sensitive data is being transmitted. After all, encrypting the pages of the sweaters you're browsing through makes no sense when you really need the protection only when you're ready to buy.