The Modern Guestbook

Did you know that the wedding guest book at one time was a requirement. In the old days, everyone who attended the wedding was considered a witness and was required to sign the marriage document. Since that is no longer the case (thank goodness), brides are starting to come up with some delightful and creative ideas for the “guestbook” which is not necessarily a book at all! For example:
With Postcards:
I will in fact be doing this for my own wedding. I am going to have my Maid of Honor mail them to us randomly during the first year of our marriage. I can’t wait!
A Wishing Tree
For a wishing tree it is great to put a sign that says “wedding wishes for the Mr. and Mrs” nearby. 
Using a Typewriter:
An added bonus to doing this: you can read everyone’s writing!
Not sure what to call this one, but I like it! 
It is kind of like a wishing tree, but with antique knobs. Guest write their advice/congratulations on a tags with string and then place it on their favorite glass knob. I was so inspired by this unique piece that I decided to make my own! Here are the results:
With the sample “wishes”
Without “Wishes”:
A close-ups of my favorite knobs:

It also could be used things other than a guest book, such as displaying old family photos. It also works horizontal as well. 
Anyone else seen any other creative guestbooks lately? I love to see new ideas!