Beware of the new scam that spammers have thought up. Now they're sending fake e-cards which can trick a recipient into opening a website or even downloading a virus without realizing it. The problem with e-cards is that people are already used to receiving these randomly (since you never know when you might get an e-card) and they have always required that you click the link in the e-mail to get your actual card.
It looks like e-card companies are going to need to address this by only putting the card reference number in the e-mail and making people come to their site directly and enter it instead of using in-email links. Chances are that the e-card companies will be reluctant to do so since any added steps or difficulty will reduce the number of users willing to look at the cards, but they may not have a choice if this scam gets out of hand.
It looks like Consumer Affairs has this story too.