Since it was first written in 1982, the Simple Mail Transfer Protocol, the mechanism for sending emails, has remained largely remained unchanged. Today SMTP delivers 70 trillion emails to 5B inboxes each year. Overwhelmed by tens of thousands of emails, most of us can sympathize with Nick Bilton, who said:

There is no escape: Email is probably most invasive form of communication yet devised.

Unlike SMTP, email is changing very quickly. In particular, email is undergoing a great unbundling, similar to Craigslist’s, in which startups are seizing upon important use cases of a generic service and building a better, dedicated version of it as a stand-alone company/product. This is happening to a certain extent in consumer products like ephemeral messaging (SnapChat) and location sharing (Glympse).

But the trend is much broader in B2B products. I’ve seen it first-hand when we switched to RelateIQ as our CRM. Instead of going to my email inbox in the morning to see what’s new with the opportunities we’re evaluating at Redpoint, I go to RelateIQ. First, to be able to see across the inboxes of my partners, and see all the companies we’re speaking to. Second, to be able to quickly find information relevant to a particular company or person: all the email/meeting history. Third, to enforce a workflow around email, e.g., timely follow-ups. All of these emails to and from startups, I handle within RelateIQ, not Gmail.

This trend of segmenting email into a dedicated, smart-inbox-with-workflow is broader than CRM. Customer support software like Zendesk is probably the oldest example of an app that segments a chunk of email and wraps it with prescriptive workflow. LinkedIn’s InMail is a similar system for recruiting. Yammer has removed water-cooler emails from inboxes. Contactually segments email for network relationship management. Similarly, I believe every major category of large volume, workflow email will be segmented into a dedicated app in this way.

Most users won’t want more than a few separate inboxes, perhaps 1-3. But those 1-3 inboxes will be disproportionately valuable because users will live in those dedicated inboxes. These dedicated apps enable users to win their time back by providing all the context users need to act upon the email. Mobile is an important driver for email segmentation because the lack of contextual information makes it even more difficult to process emails than usual. Machine learning is a second key enabler because it enables filtering, categorization and smart reminders.

At this point in email’s unbundling, the volume of email in our business inboxes hasn’t declined, and it may never decline because most of the automation is on the outbound side, making it easier and easier to send larger volumes of email. When both sender and receiver have intelligent workflow apps or are trained to log into workflow apps first, the most effective way of reminding users to return to workflow won’t be email reminders or push messages. And then, perhaps email volumes will fall.

But, even if email volumes don’t decline, workflow-based email products will enable us to process much larger volumes of email than we are today.