Eclipse Milo does have an active user base coming from the original project at "digitalpetri". It was presented as a new project during EclipseCon Europe 2016 and several IoT projects are interested in interfacing or integrating Eclipse Milo.
During the first release a new commiter was added to the project.
Due to the fact that Milo is a library/module with no direct end user involvement it is hard to give any details about end user activities.
The community is working on GitHub at https://github.com/eclipse/milo.