A great email subject line is valuable, but targeting your message to the interests and preferences of your audience is even more important. If you can get someone who trusts and supports you to forward a message, that's worth more than a list. 

Quora: What is a good way to start promoting a church or business? 2019-Dec-4 by Paul O'Brien of MediaTech Ventures

Where once, a message sent was likely received by all (or at least most), now the two way relationship between communicator and receiver has changed; with the receiver being empowered to decide HOW and WHEN they receive. The communicator must participate on the receivers’ terms if they hope to be heard…. 

We used to live in a world where that 1 email, that one meeting, that one office flyer, or that one letter mailed, would reach and communicate with everyone. If I can impart upon you ONE lesson only, it’s that that no longer works.

Trickle down your communication to distinct groups, who can further and more effectively communicate what matters within their audience….

Where one-to-many… and newsletters fall short, is that they think in terms of the quality of the email exchange or the performance of an email sent. That is, they’re optimized for reception and engagement….

In organizational communication, our key metric isn’t an open or conversion rate, it’s KNOWING our “clients” and serving them meaningful communications.