Google has added a new inbox sorting feature to Gmail. This can be nice if the email workflow suits you. However, it can really hurt your email marketing efforts.
The problem with this very simple. Many of your clients and potential clients might not realize that the new sorting tabs are there. That means if you send an email and it makes its way to Promotions then the recipient may not see your email.
I’m not going to go into this too much because Kristi Hines already explained it very well. Please visit her article on why you should care about Gmail’s new tabs.