At Sparx Systems, our staff regularly use Enterprise Architect's inbuilt "Model Mail" throughout the day, sending messages regarding tasks and work items. The Business and Development staff alike use Model Mail to collaborate, and it has always been handy to link to what we're working on.
Functionality added in version 13.5 made it even simpler to link to model Artifacts. While modeling in context, users can simply right click on the Artifact in question, be it an Element, Package or Diagram Package, and select Collaborate -> Send Message to bring up a new Model Mail dialogue that includes a link to the Artifact embedded in the message body.
Context Menu -> Collaborate -> Send Message
A link to the Artifact and relevant Diagram is then visible in the message body.
It's that simple, and it can simplify your correspondence considerably.