Verizon and AT&T have opted out of the 50GB Dropbox cloud storage promotion for their versions of the Samsung Galaxy S III. The news comes from Dropbox itself, which states that "select carriers have opted out of the promotion" and "Verizon and AT&T are among these carriers not participating."

The promotion, available internationally, adds 48GB to Dropbox's regular 2GB free allowance and runs for the length of an average contract. The deal doubles that offered by HTC's One series, which adds 23GB to boost storage to 25GB. Neither Verizon nor AT&T has commented on Dropbox's announcement yet, but we'll let you know if they explain their decision.