Great for giving others directions to your place. All you have to do is read the email which is basically an ad or commerce site and you receive points. You can cash them in for gift certificates. You'll need a plugin which is also free. Animated Greeting Cards - Send cards through email.
Animated cards are especially fun.
Egreetings has some more adult choices. Bluemountain greeting cards - Bluemountain is pretty good for kids. Internet Help - Similar to the services above except it is live help and it is web related rather than computer related. Jelly Belly - I received 2 packages of jelly beans this summer. They give out 100 sample packs every day.