While Apple is celebrating six years of App Store action with more than 75 billion app downloads served and over $15 billion paid to developers so far, a new report from app analytics company Adjust says that 80% of apps available in the App Store are “zombie apps,” or apps that aren’t easily discoverable by the users. According to the company, to qualify as a Zombie App, an app must not rank on any of the 39,171 App Store top lists on two out of three days over the month. While App Store app discovery has been criticized before, it’s not clear what the correlation between Zombie App status and developer revenue is, as the Adjust doesn’t reveal such stats. Similarly,