On Friday, Nullriver Software announced that Apple removed their iPhone application, NetShare, from the App Store. There was no prior communication from Apple.

Nullriver’s Website had this note on Friday:

We’re not quite sure why Apple took down the NetShare application yet, we’ve received no communication from Apple thus far. NetShare did not violate any of the Developer or AppStore agreements. We’re hoping we’ll get some feedback from Apple today. Sorry to all the folks that couldn’t get it in time. We’ll do our best to try to get the application back onto the AppStore if at all possible. At the very least, we hope Apple will allow it to be used in countries where the provider does permit tethering.

Tethering is a process whereby a notebook computer user can use their connected mobile phone to gain access to the Internet via the 2G or 3G network. According to Tech Crunch on Thursday, such tethering violates AT&T’s terms of service, and that could explain the absence of tethering apps for the Apple iPhone.

iPO contacted Maksim Rogov at Nullriver Software to find out more, but all he could report was the public statement above. Apple still has not contacted him with an explanation.

If tethering software is indeed prohibited by AT&T, that detail could have slipped by Apple’s staff since it’s not prohibited in the Apple SDK agreement, according to Nullriver. Such carrier prohibitions may not be in effect in other countries.