"Content is no longer king," Craig Spiezle, director of online safety strategies and technologies at Microsoft, told Email Insider Summit attendees last week. "If you don't have email authentication, your emails are going to be throttled."

Unfortunately, email authentication and deliverability are growing issues that were much talked about at the Summit -- unfortunate because these kinds of issues push email back down into the IT realm instead of elevating it to a more strategic stature that's at home in C-suite discussions. Email authentication is an automated process that verifies an email sender's identity and is designed to eliminate spoofing and reduce spam.

Microsoft's Sender ID and Yahoo's DomainKeys are the two major standards. Spiezle, who presented email authentication as the golden path to deliverability, said that 43% of legitimate email volume is certified by Sender ID, and he later told me that adoption is north of 85% among volume email marketers and that 9 million domains have been authenticated. Miles Libbey, office of postmaster at Yahoo Mail, who also spoke at the Summit, didn't say where DomainKeys adoption stood, so I decided to check out the adoption rate among the 100 or so retailers I track via RetailEmail.Blogspot.

What I found was that DomainKeys adoption currently stands at 48%, very close to being in the majority. Soon, if you haven't signed up for DomainKeys, you may have to explain why you haven't.

However, the list of non-adopters includes some very big national brands, including Wal-Mart, Dell, Home Depot, Target, Gap, Macy's and Circuit City -- all of which you'd think would have concerns about both spoofing and deliverability.

The other interesting thing I uncovered was that DomainKeys adoption doesn't seem to have any relation to the frequency of a retailer's email program. I thought that retailers sending the most emails per week would be the most likely adopters, so I looked at retailers sending more than two emails each week on average during the past 12 weeks. However, only 45% of those retailers used DomainKeys.

Looking to the other extreme, I thought that less frequent senders might be bigger adopters, but those sending one or fewer emails per week were even more likely to be non-adopters, with only 44% onboard with DomainKeys. That left the folks in the middle, those sending more than one but no more than two emails per week, as the outsized adopters, with 54% of them using DomainKeys.

I sincerely hope that email authentication fulfills its promise and fixes many of the deliverability problems marketers have while simultaneously reducing the amount of spam. The sooner we get these "blocking and tackling" issues out of the way, the sooner we can get back to focusing more on the actual content and strategy of our emails.