In what looks like a well-established trend over at Apple, the Cupertino-based iPhone maker has excluded another important application from the App Store. Nullriver's NetShare had previously gained access to the venue, after which Apple (or AT&T) decided to pull it from the store. The app got itself back online, and now, for the second time, Apple has denied its presence on the App Store.

We wouldn't want to start referring to the App Store as "controversial," should more app pulling be in order, but it seems that Apple's unwritten rules are starting to take their toll on ever more iPhone developers, with some of them even refusing to continue development on their respective apps.

When Nullriver officially released NetShare, an Apple-approved iPhone tethering application, onto the App Store, the company stated that "the purpose of the application is to share an iPhone's Internet connection with other devices over Wi-Fi, essentially making the iPhone into an on-the-go Wi-Fi hotspot." This, however, seemingly forces AT&T to pay for more bandwidth. The application was available for a short while (for $9.99) on the App Store, meaning Apple had initially given its approval for it.

Later, however, NetShare was taken down, leaving hundreds of tethering-hungry mouths crying on Mac-based forums. While NetShare itself is a bit controversial, still, it is Apple that needs to clarify the limitations regarding tethering apps, by disclosing them in the agreement with developers. For its part, Nullriver issued a response to fans, claiming it had no idea what had happened, although it was pretty obvious that the app would make some waves.

"We're not quite sure why Apple took down the application yet, we've received no communication from Apple thus far," Nullriver said in July.

After a while, the app was back up, and, before they knew it, Nullriver saw it pulled again from the App Store. The company's most recent post reads:

“Looks like Apple has decided they will not be allowing any tethering applications in the AppStore. As such, NetShare will not be available in the iTunes AppStore. We are seeing a lot of similar reports from various developers whose applications were abruptly removed and banned from the AppStore without any violations of the terms of service. This is all unfortunate news for the iPhone platform end-users.”

Nullriver upholds that NetShare does not violate any of the Developer or AppStore agreements.