App discovery is a problem for Apple's App Store, and the company is hoping to improve the situation with a new Explore tab in iOS 8. But as we wait for Apple's newest mobile OS to roll out this fall, Apple is starting to crack down on a number of questionable methods app developers use for promotion and bringing in ad revenue.

Several developers are turning to online forums to complain that Apple is rejecting apps that use techniques such as rewards for social sharing, as well as advertising apps inside other apps, as first reported by TechCrunch.

Incentivized to not incentivize

Included in the new app purge are games that reward you with in-game currency or extra lives for sharing a link to the app on Facebook and other social networks. Additional types of incentivized actions are also out, such as watching video advertising for another app to gain in-game progress.

UK-based iOS developer Dan Sinclair took to Stack Overflow to complain that Apple rejected one of his games for incentivized video views--an advertising method he has included in his apps several times before.

Sinclair doesn't say which of his apps Apple recently rejected. However, after downloading the current version of the developer's "Catch The Critters--Free," I was prompted to either buy extra lives or watch a video to gain a life after just one round of play. This is exactly the type of ham-fisted activity Apple apparently wants to discourage.

Several other developers on the iPhoneDEVSDK forums also complained of rejections for using incentivized actions. One developer said Apple rejected his app because it gave a "free hint to users when they share the app on Facebook."

Confronted with the choice, most users would rather suffer through a commercial than fork over cash to get their next life. But constantly jumping through hoops just to continue playing a game contributes to a very poor overall experience. It's about time, then, that Apple got tough on these practices.

No third-party advertising in third-party apps

Apple also appears to be going after apps that make a point to advertise apps from other developers. Sinclair wrote that Apple also rejected his app because it had a section labeled "More Apps" that included links to, you guessed it, a number of other apps.

The problem isn't advertising apps inside other apps, per se. Apple would be totally fine if Rovio plugged Angry Birds GO! inside of Angry Birds Star Wars, for example. Branch out to advertising apps that aren't your own, however, and developers apparently risk the wrath of Apple.

Creating a mini-app store inside another app probably isn't all that offensive to most users. For Apple, however, it means handing over app discovery to non-sanctioned sources. Apple also appears to be arguing that this type of advertising can unduly influence App Store rankings, which is a no-no in Apple's book.

Cracking down on at least some of these practices is definitely a win for everyday users. But as TechCrunch points out, incentivized sharing is not unique to smaller developers. King's uber-popular Candy Crush, for example, asks people to share on Facebook to gain more lives. It will be interesting to see if top games that use these practices will also have to adhere to Apple's latest policy enforcement, or if they'll get a pass.