Want more proof that the most modern of royal couples is firmly entrenched in the digital age? Not only do they have a wedding website, but they're steering their well-wishers to a YouTube "message book."
On the video-sharing site, the channel for Britain's royal family, The Royal Channel, you can upload a video of yourself offering good wishes to Prince William and his bride, Catherine Middleton. Now, we've suggested a video guest book before, as a lively variation on the photo booth, but opening the channel up to people who can't attend, as William and Kate have, is an extra-nice treat.
Instead of sending the videographer around the room to interview people at the wedding -- it's a little old-hat by now -- follow in the royal couple's footsteps and take it online.
What will you do for your guest book? Need some ideas? See our gallery.