Think email deliverability is an obscure concern? Think again: Globally, email deliverability rates, the rate at which emails actually arrive at their intended inboxes, is woefully low. [ReturnPath](http://www.returnpath.net/) found that nearly 25% of commercial emails never make it to their destinations, an alarming percentage that increased quite a bit in the second half of 2011. MarketingCharts tells the whole [story](http://www.marketingcharts.com/direct/1-in-4-commercial-emails-did-not-reach-inbox-in-h2-11-21571/?utm_campaign=messagesystemsblog&utm_source=mc&utm_medium=textlink).