A random posting on a site earlier this week alerted me to the fact that Prince of Persia Retro is gone from the App Store. I still have it on my iPod and my laptop but I wish there was some way to track apps that have been deleted, so I can take extra steps to keep a copy safe for the future. Is there any way to do this?
Nope. Nor is there an easy way to foresee an app update that breaks / removes functionality / includes advertising. So, here's what I do: About once a week I copy my Mobile Applications folder to a backup drive. This allows me to backdate apps if I need to, keep things when they're gone from the App Store, and delete them from iTunes if they're not on my iPhone so that iTunes doesn't bog down too much. (To put this in perspective, there are right now 654 apps on my iPhone. )
That's a good idea. I'm going to start keeping a backup on a storage drive, that I'll update every week or so. I had been using Time Machine backups to keep old versions for the reasons you mentioned above, but ran out of space after reformatting my MacBook (it made a backup of the entire drive again, and deleted most of my old backups to make space for it...). I was thinking there might be some way of scanning the apps folder and checking the App Store. Kinda like how the AppShopper app works, but I'm not much of a programming guru.