But what do you sign in a digital age? I think it's a token/memento which will always be important to collectors and devoted fans. I know I wouldn't part with signed books. They are special. they are touched.
I think there are a few possibilities for signatures in a digital age.
1- being e-readers adding a touch screen so that authors signatures can be collected. Who knows, there is probably already an app for that... And if not I demand 50% of your profits!!
2- Comes from Japan. Manga artists often sign shikishi boards at events. They are wonderful mementos and can be displayed in frames and wall hangings http://www.samadhicushions.com/Shikishi_Calligraphy_Board_10_pack_p/s-3044t.htm
Since I can draw I vote for shikishi boards!