I bought a Levenger Shirt Pocket Briefcase in December, and have also noticed that one end of the cards sometimes pops out. I don't use mine very often though. This was a purchase I made without thinking about the practical application first. I work in a business casual office environment, and most of my winter shirts do not have pockets. So, I rarely carry it. I'm using a PocketMod stuffed in my pants pocket these days instead.
Sometimes, the best note taking tool (as you've ) is a pen and paper. The Levenger Pocket Briefcase takes that idea and adds it to your wallet, by integrating 3x5 cards and a writing utensil into the wallet you're probably already carrying around in your pocket. There's no startup, no apps, and no autocorrect messing up what you're trying to type—just quick note jotting.
The Levenger pocket briefcase runs for $69, which seems hefty until you realize your wallet probably costs the same amount. If you don't want to shell out the cash, of course, you could probably just integrate this idea into we've featured at Lifehacker (or just go the other direction and ). Hit the link to check it out.
Smartphones are great for note organization, but sometimes taking notes on them can be quite slow. The Levenger Pocket Briefcase takes pocket note-taking old school by integrating pen and paper with your wallet.