The smart span filtering algorithms of the internet service providers make it difficult to reach the user's inbox with advertisements. So to take benefit of the email marketing, you need to keep few things in mind. One needs to integrate a HTML button in your email that is coded as Call to Action (CTA). These make the emails responsive. HTML buttons help in building and engaging traffic. A well designed HTML email reinforces your brand even in the email. The HTML button is visible before the images get loaded. According to a report, the majority of the online purchasing begins from the mobiles. So the emails should be very responsive for these devices. The three components needed for this are: Right breakpoints, Larger Text on Mobile Devices, CTA buttons. Read more about it on: http://blog.marketo.com/2015/12/3-email-marketing-must-haves-to-conquer-the-inbox.html