Apple published its entire response on its Hot News website. Apple first of all states that the official Google Voice client hasn't actually been rejected, and that they're still studying it. As John Gruber notes, this is merely "splitting hairs" (Apple has been studying the application for ten weeks now), however, it is a good thing that Apple may still reconsider. Interestingly enough, Google itself also never claimed the application was rejected.
Getting to the meat of the matter, why doesn't Apple approve the Google Voice application? Well, according to Apple, it alters the iPhone's core user experience, especially when it comes to dialing, voicemail, and SMS. However, as also noted by John Gruber, this raises two interesting questions: one, why were other (i.e., not written by Google) Google Voice applications approved to the App Store, only to be removed when Google's official client came in? Two, why are various other applications admitted into the App Store that also deal with the dialer and SMS? "Try searching the App Store for 'dialer'," Gruber notes.
Another complaint by Apple about the Google Voice application is that your contacts are uploaded to Google's servers. "The iPhone user's entire Contacts database is transferred to Google's servers, and we have yet to obtain any assurances from Google that this data will only be used in appropriate ways," Apple writes, "These factors present several new issues and questions to us that we are still pondering at this time." Update: Apparently, iTunes already provides the ability to sync your contacts to Google Contacts, making this complaint from Apple rather dubious.
We can clear one thing, though. Many assumed that it was AT&T's bidding that meant the end of all the Gogle Voice applications in the App Store, but both Apple and AT&T are quite clear that it is Apple, and Apple alone, that made the decision. Furthermore, AT&T has no influence over the App Store whatsoever. However, Apple does note a provision in its agreement with AT&T that states VoIP services require AT&T approval.
What I found quite interesting is the description of the App Store approval process. As it turns out, there are over 40 people dealing with all the App Store submissions, and each application gets reviewed by at least two different people before a final call is made. They handle 8500 submissions per week, which means that each reviewer handles - at least - 425 submissions per week (8500/40 multiplied by two because of the at least two reviewers per application policy). I can see how having to review 425 applications every week will eventually lead to faults in the process.
In addition, Apple mentions an executive review board. "Apple also established an App Store executive review board that determines procedures and sets policy for the review process, as well as reviews applications that are escalated to the board because they raise new or complex issues," Apple details, "The review board meets weekly and is comprised of senior management with responsibilities for the App Store. 95% of applications are approved within 14 days of being submitted."
Moving on to Google, its letter details the workings of Google Voice, but the answer to question 2, which asks Google to divulge the reasons given by Apple for not approving the Google Voice application, are censored. Google's letter also details the approval process for the Android Market (namely, there isn't one), and notes that Android users and developers are not tied to the Market at all, and are free to install applications in other ways too.
The last certainly hasn't been said on this issue. Let's wait and see what the FCC thinks about the responses.