Daniel Koller has created an Apache ESME Mailet as a plugin for the Open source Mail Server Apache James which allows users of an Apache ESME infrastructure (both humans and technical systems) to send email messages to an Apache ESME instance using their own identity. Messages sent through the mailet show up as personal messages from these end users, so people following you get them in the respective blogging timeline.
The install guide is available on Google Docs.
This new functionality is especially useful for integrating legacy applications into the Apaache ESME environment inasmuch as many such applications might not be able to integrate via the REST API but usually have the ability to send emails. Furthermore, an email interface also allows users to post Apache ESME messages with mobile devices.