Can other cable modem users see the data I send and receive?

As with ALL network connections, there is always a vulnerability.  While it is true that Time Warner Cable sends all the downstream Internet traffic for your neighborhood to all the cable modems in your neighborhood, every byte is encrypted using the widely-used DES encryption algorithm designed by the U.S. government.  Also, in addition to being encrypted, data sent from your computer to the Internet is never sent to other cable modems in your neighborhood.

You should always be careful when sending sensitive information over an Internet connection...cable, dial-up or otherwise. Your web browser's documentation has more information about how you can use encryption to maximize data security.