Fewer Gmail Users Are Opening Retailers' Messages This Shopping Season - NYTimes.com

It'll be interesting to see how Google reacts to this data

"Half a year since Gmail introduced tabbed inboxes, fewer emails from retailers are being opened, according to three services that manage mass emails. And while some data showed that Gmail users nonetheless spent more money — perhaps because they proactively sought out retail emails in the promotions inbox — other data showed the opposite.
Gmail shoppers, who tend to be wealthier and more tech-savvy, clicked on retail emails 14.5 percent more than Yahoo users before the change to Gmail, according to Epsilon. But by October, the difference had shrunk to 4.2 percent, indicating that Gmail users were ignoring marketing emails more often."

Fewer Gmail Users Are Opening Retailers' Messages This Shopping Season - NYTimes.com