The media enjoys playing up the idea that using your credit card online is
very dangerous. I'd like to point out that there are very few differences
in using your card online than in person.

The largest precaution about using credit cards online is knowing who you
are dealing with. You wouldn't go around giving your credit card number
to a street vendor who is working out of the back of a run down Yugo
without knowing who they're affiliated with or what guarantees they
have. This is true for online stores too.

The second issue is actual security. Your normal name brand online vendor
will be running a somewhat secure site. The data between your computer
and theirs will be encrypted and for the most part, safer than your retail
store. Have you ever noticed the receipts at your local Radio Shack or
other stores being put into a bin behind the counter? It would be easy
for someone to walk in, take a stack of receipts and walk out in most
cases than it would be for a "hacker" to attempt to hack the server and
steal your card information.