Thank You Card Etiquette from The American Wedding:
Traditionally, wedding thank you notes, as with any heartfelt correspondence, should be written in your own hand, your own words, and in a spirit of humble gratitude for the intended recipient. Experts can literally tell gender, age, education level and emotional state from examining samples of a person’s handwriting. A handwritten note conveys more than just your words; it conveys your emotions, your personality.
Practically, think of it this way: What would mean more to you coming from your spouse-to-be? A three page Word document professing their undying love for you and quoting Shakespeare? Or a simple sticky note “I Love You” left for you to find when they know you’ve had a bad day? Which are you more likely to keep, remember, cherish time and time again?
All of us prefer to receive correspondence that makes us feel special, cared for, thought about. In today’s fast-paced world, it is much easier to send out a mass email thanking all your wedding guests for their attendance and gifts than it is to take the time to sit and write a hundred paragraphs of heartfelt, individual communication. Taking the time to do just that, however, is part of what makes your thank you note mean so much to those you cared for enough to invite to your wedding in the first place.
In many cases, thank you notes are your first personal communication as a married couple. They should reflect your joy, your vision for your future together, and a sense of shared gratefulness for the friends and family who gathered to bear witness to your wedding, shared in that moment with you, and wished you the best life has to offer. Somehow, an emoticon smiley face just doesn’t seem like enough.