Receiving or sending cards from the website card shops
This is a hard one to avoid because it will be a friend or relative who gets you signed up for this one.
To send a card the sender has to put your address in (obviously) or you won't get the card but then they also need to put their address in as well. Most of the people who have ever received a card of some sort have also received the ad to purchase a signature to ad to your e-mail or you get an e-mail from that mailer that says they will revolutionize your e-mail and send spinny things and blinky pictures within your e-mail. Great, that's just what we need!
Have you ever got one that says 'You have a secret admirer, click here to find out who it is'? This one is normally just to verify that your address is a valid one and can be indexed as soon as you click on it.
Here is another one you can think about; next time you go to get that e-card it has now been classed as a virus E-Card virus.
At least there may be some salvage to the damage a friend can do by sending you a card this way they do seem to have to show you a disclaimer first before you get the card so the best thing to do would be ...
Bottom line .... delete any messages that come and say click here to receive your greeting card if you click this will verify that your address is real and if you never go to get the card you may be removed from the index.