It is thus important for Google to convince businesses that storing data in Google facilities is safe, despite the events of last month.

Sullivan, in his noted that he has been moving more and more data into Google services but is rethinking that strategy in the wake of Google's security troubles. He criticized Google's insistence that the attack was not an assault on cloud computing.

"It was very much an attack on cloud computing, as Google's main blog post made clear," Sullivan wrote. "Hackers went after Gmail accounts, not just through malware-infected computers but directly by targeting Google, that post told us. Gmail — your e-mail, stored in the cloud. That's an attack on cloud computing."

Cohen in his own blog post, saying the attack doesn't reveal any deficiency in cloud security because hackers used social engineering techniques to gain access to private systems.

"What this hack really proves is that people are easier to hack then networks," Cohen writes. "The weakest links are the people who are stupid enough to open an attachment they don't recognize, even if it appeared to be from someone they trusted. That's the beauty of social engineering based hacks. The e-mail appears to be from your mother, father, friend or colleague. The lesson we must learn is one of education, don't open attachments you don't recognize."