Here is a prelude to why the iStat App was removed from the iTunes Store. Apparently, Apple had made a bold announcement aimed at the app developers to remove the “Free Memory” function or be deleted. There was no specific reason given on why such a directive was handed out by Apple.

The free memory feature is a helpful app that accomplishes its task by allocating memory until the iPhone OS detects a critical low memory level and starts terminating other background processes.

iPhone owners who want to avoid a complete device restart should force quit Mail, Safari, and iPod, if necessary, and then hold down the sleep-wake button until the red slider appears. After that, down hold the home button as well until the application quits. Now why would Apple want to do away with that?

(Source) iPhones Talk