Inbox placement is different from deliverability. Your delivery rate is the percentage of emails that make it through the ISP’s or email administrator’s gateway and are passed on to the subscriber, member or customer. But many of these messages never make it to the inbox because of local spam filters, rules which siphon off messages to different areas, and inbox management applications. Knowing that your messages are not hitting the inbox and therefore not read right away is an advantage you can use.
So what to do? To encourage your contacts to keep your messages in the A-List and mark them for inbox placement, try time-sensitive offers in your emails and then use your social channels to let people know they are coming to the inbox only. Your social engagement acts as a catalyst for email engagement that can result in higher response rates to your email offers.
For more information, check out:
How to Use Social Media to Drive Email Subscriptions: http://www.slideshare.net/deliver2inbox/social-media-23899679
How to integrate your email campaigns with social channels: