AT&T has a history of limiting its Android handsets to only be able to install apps purchased from Android Market, which means that unlike Android smartphones from other carriers, the smartphones offered by AT&T cannot have side-loaded content. This issue was found on Motorola Backflip, the carrier’s first Android smartphone, as well as the new HTC Aria. For its part, AT&T is defending its move, stating that the limitation allows for quality apps that are curated by the community and by Google as well as to prevent the introduction of harmful software onto the open-source OS:
AT&T selected Android Market as the exclusive source for applications because it forces developers to be accountable for the apps they submit. If the Android community has issues with an app, the app can be flagged and removed. This minimizes the risk of malicious apps harming customers and provides more protection to the customer’s private data stored on the phone.