# It fits easily in your back pocket or purse.Link (Thanks, Dan!)
# It's as cheap as one piece of paper (Because that's all it is!)
# It opens like a book. Leading to easier to find, more organized notes.
# The first page has a pouch, big enough to carry a business card!
# Customizable with "Mods" tailored to your needs.
# It's free and fun!
Update: Eric sez, "If you think PocketMod is cool, you should take a look at Douglas Johnston's D*I*Y Planner, a series of lots of templates distributed under a Creative Commons license, including a 'widget kit' in OpenOffice.org Draw format to assist in creating your own! The D*I*Y Planner is available in several sizes (including 'Hipster PDA' index card size), and new templates are included in every release."
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.