With email inboxes more crowded than ever before, simply arriving successfully is half the battle.  Assuming you routinely have good deliverability, the second half of that battle is standing out in a crowd. The majority of email users (more than 70% by some estimates) view the lineup of email messages in their inboxes via preview panes, so only a snapshot of each message is visible either to the right or on the lower half of their screens.  Mobile environments can be even worse, eliminating preview-ability altogether.  

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