Google has initiated a new form of advertising into Gmail

Summary: Gmail ads now appearing as emails into a new type of email popping up in the Promotions tab

Recently Google has upgraded gmail service by sorting emails into tabs. There are five types of tabs at this time; these are Primary, Social, Promotional, Update and Forum. It appears at the setting. Primary is for newsletters and correspondence; Promotions is for marketing offers and deals, such as Catch of the Day, Social is for updates on social networks, such as Twitter and Facebook.

However, users have been noticing a new type of email popping up in the Promotions tab: paid-for-placement advertising. These are in addition to the ad bar that shows up at the top of the page and column on the right-hand side when you open an email.

They are differentiated from regular emails by a shaded background and the word "ad" appearing below the sender's name; users can open them and read them like a normal email, with information on the promotion inside with links and videos. You have the option to forward to a friend or dismiss the ad; if you dismiss it, you won't receive that particular promotion again.

Source: Gmail ads now appearing as emails