Be on the look out for this on your next credit card statement.
But it's just a quarter... (http://www.boston.com/business/personalfinance/articles/2009/01/11/mysterious_credit_card_charge_may_have_hit_millions_of_users/?s_campaign=yahoo)
No one really knows what's going to happen next, but if you see the charge you can at least be certain some unauthorized party has gotten your number and your card is no longer safe.
Clever, but almost a little too small an amount.
People would never make a real 25c charge on their credit card, if they'd raised it to $1.50, it would be less suspect as the person could think they may have made the transaction and forgot about it.
In either event, it's clearly a good strategy. Scam a small amount off a huge amount of people. Unfortunately, posts like this one show that even this strategy can be blown (ironically using the same technology that brought so many available credit cards in the first place: the internet).
I know a real sneaky scam involving a small cahrge on your credit card to watch out for...
http://www.snopes.com/fraud/sales/express.asp
of course, the guy doing it was caught, but...