A new Artificial Intelligence sub-system within Google’s email security system can identify some items that are outside of normal standards and these will be delayed & further analyzed to protect end users. This new security improvement has occurred due to recent attack on Google Docs as documented below.

http://www.pcmag.com/news/353978/google-delaying-some-gmail-messages-to-quell-phishing

Google already blocks 99.9 percent of spam and phishing messages from showing up in your Gmail inbox. Now, the web giant is rolling out four new Gmail security features for enterprise customers to help prevent the other 0.1 percent from making it through and tricking you into handing over your company’s private information.

That includes early machine learning-based phishing detection, new warnings when you click on a phishing or malware link in a message, as well as “unintended external reply warnings, and built-in defenses against new threats,” Google’s Senior Product Manager for counter abuse technology, Andy Wen, wrote in a Wednesday blog post.

“Now, if you try to respond to someone outside of your company domain, you’ll receive a quick warning to make sure you intended to send that email,” Wen wrote. “And because Gmail has contextual intelligence, it knows if the recipient is an existing contact or someone you interact with regularly, to avoid displaying warnings unnecessarily.”

Online miscreants last month launched a massive Google Docs phishing attack, which hit a number of journalists and individuals from other industries. Clicking a purported Google Docs button in the nefarious message took users to an actual Google page, which asked them to grant access to an app masquerading as Google Docs. Those who inadvertently granted permission gave the attacker full access to their email messages and contacts.