Heya!
It's fun to do something on your own. To create a useful thing out of useless materials is really really awesome. Here are my realization about creating a bookmark from scratch.
Pros:
1. It's a corner bookmark. Hence, it wouldn't create a space in the spine of your book, specially if you were not able to remove it for days.
2. Very light weight. It will not dent your beloved pages.
3. You can create different facial expression of bookmarks. Create and Make!
Cons
1. It is made of paper. Not water proof. (unless it is okay for your book to get wet)
This is where I got the pattern for the corner bookmark. (http://tallystreasury.com/2011/02/corner-page-bookmarks-3/). Tally Treasury is a jam-packed blogsite for all the DIY craft tutorials you need. Thank you for the inspiration!