Answer
Click on
eCards in the top nav bar, then click on
My eCards button. You will see a list of your eCards with a
Tag Button
next to each public eCard (only public eCards can be tagged). Click on the
Tag button for the desired eCard, and enter your tags in one at a time and press the "Submit Tag" button. Your tag will appear on the
eCard Tags page, and your eCard will be listed when someone clicks on your Tag.