If you or your business don’t regularly use Gmail (or you haven’t switched to tabs yet), here’s what everyone has been talking about: At the end of May, Gmail announced the slow rollout of a new layout, switching users from a single inbox to a series of tabbed inboxes, set to filter different types of messages.

The "Promotions" tab grabs deals and marketing emails, while the "social" tab catches messages from Twitter, Facebook, LinkedIn, and other networks. Priority is given to the "Primary" tab, where everything else lands. And because alerts for the secondary tabs are more subtle, recipients may not immediately notice new promotional emails or social network updates.

While some users have been having adjustment issues, there are plenty of fans: Slate’s Will Oremus wrote a love letter to the new inbox, calling it “fantastic … the best thing to happen to email since the original Gmail. ” And, since part of what Oremus raves about is the ability to segregate promotional emails, he notes that, “The one group of people legitimately terrified of the new Gmail is email marketers.”

If you rely on email marketing, should you be terrified?

The Outlook for Open Rates

On Tuesday, Matt Grove of MailChimp, an email marketing service provider, posted an analysis of 6 weeks of statistics to the company blog. His conclusion? “A small but definite drop” so far, with weekday Gmail open rates falling from above 13% to slightly more than 12%. 

Other companies have seen similar drops. According to Tom Sather, Sr. Director of Email Research at Return Path, open rates have declined by .5%, but only for desktop users. Since mobile devices don't the new tab system, he said, "the effect might be lessened as more users shift to mobile." 

Gail Goodman, CEO of web marketing company Constant Contact, said the small movement downward is "nothing alarming." She noted that it’s still too soon, in terms of both the rollout and Gmail users adapting, to identify any longterm patterns. "Our advice is: don’t panic." 

In fact, Goodman suggested, it’s possible this could ultimately result in "drawing consumers to promotions in a different pattern than they’re doing today." Rather than getting lost between personal emails, the tab system might allow users to deliberately look for promotions at a time that’s more convenient for them.

What's an E-Mail Marketer to Do?

Sather offered some immediate suggestions for email marketers hoping to stand out, including "extending email campaigns to give time to your subscribers to check their promo tab" and using dynamic content that lets offers refresh whenever the email is opened. Companies might also ask subscribers to mark their emails for the primary inbox.

For now, Goodman recommended that small businesses, particularly those with loyal customer followings, hold off on making any changes to their marketing strategies, such as attempting to land in the primary inbox. On a practical note, MailChimp’s Grove pointed out that, "Even if we did find a tricky way into the Primary tab, they’re smart over there, and they’d more than likely address any reasonable workaround."

As the inbox rollout continues, it will be interesting to see how the situation for email marketers plays out. MailChimp has promised to update their stats once they have more data. For any entrepreneur whose business depends in part on email marketing, this bears watching.