Sometimes the internet is a great source for tips, and this week, that tip comes in the form of something that should be common sense, but doesn’t appear to be for everyone: posting credit card details on social networking.

Twitter is a great place to find where people are doing this, with the Twittersphere practically going into overdrive to retweet when someone lacks the common sense to realise that publishing a picture of a new shiny credit card might not be the best idea.

One such account – @CancelThatCard – seems to be a good indicator of just how many people are doing this, and all you really need to do is take a wander through the account’s timeline and check out the conversations to see pictures of people doing this very thing.

We probably don’t have to explain it to you, but just in case we do, here are some reasons why taking a picture of your credit card and posting it online to any social network is a bad idea:

Posting pictures (or information) to a social network is often public

It might sound obvious, but there are a lot of people who just don’t seem to understand that most people have relatively open security settings for social networks.

If your Twitter or Facebook profile is protected with security settings, it’s a little harder, but essentially, even if you upload the picture to one of the picture services used by these networks, someone can still find it and show it to the world.

Not all shopping systems require a verification number

Online shopping has become a lot more secure over the years, what with the invention of the card security code, which in this country is often called the Card Code Verification (CCV) or Card Verification Number (CVN).

This is a series of numbers found on the back of the credit card that act as an extra security layer beyond the combination of credit card number, card owner name, and expiration date.

But there is a catch: not every shopping system requires it, and quite a few phone-based shopping services won’t bother with it, so even if you post a picture of your credit card and don’t tell anyone your CVN or CCV, you’re essentially posting all the information someone needs to make a purchase in your name.

Credit cards are personal, and you don’t just hand them to everyone

Even if you’re really proud of your first credit card, sharing it is a bad idea.

Your credit and debit card is your entry mechanism to your bank account and credit card account, and so naturally, you’re not just going to hand it to anyone and let them take advantage of it.

That’s common sense, and people generally don’t just hand money out, so why is this any different?

By publishing a picture of a bank or credit card, you put your financial details and money at risk.

Let’s not beat around the bush here: publishing details that let anyone else gain access to your money is stupid. Really stupid.