Facebook announced today an experimental service (Say Thanks) that allows you to say thank you by sending personalized video to your friends.
The new service (when available) will allow you to select a theme, photos and publications For the creation of a video. Once you've created it, you can share it with a message on your timelines or your friend's timeline.
Of course, the website containing the tool still shows an 404 error, (facebook.com/thanks), but as Facebook says the new feature will be released over the next few hours.