I saw a card with attached bookmark by Lisa Curry and just had to try it myself. Mine does not incorporate the bookmark into the card image but for a quick card I think it looks pretty good.
The bookmark is the square in the upper right corner. I used the Medallion stamp and Melon Mambo ink. It is mounted on Rich Razzleberry - I'm so glad those IN colors are now part of the Core Color Collections. The small image is from the new Level 2 hostess set Cute by the Inch.
The card looked a little plain so I decided to do a little embellishing. I added the Rich Razzleberry grosgrain ribbon which is not available currently but there is a 5/8 inch grosgrain ribbon available in 13 colors and Rich Razzleberry is one of them. The pearls are the largest of the Jewels - Basic Pearls. I used the horizontal slit punch to make an opening for the ribbon in the fold of the card. That could be done with a hobby blade or paper cutter (the slit punch is retired).
This photo shows the card and bookmark as separate items. I'm going to have to try more of these with different stamp sets. What a thoughtful little addition for those friends and family that are avid readers!