Using them together.
THE PRINCIPLE
Email reaches people who already know you. Other channels reach people who do not.
They serve different purposes and work better together.
PRACTICAL COORDINATION
Publish an article on your site Send a newsletter linking to it Post about it on social media, linking to the same place
One piece of work, three appearances.
FOR A CAMPAIGN
Announce it by email first, to the people most likely to act.
Then socially, for wider reach.
TIMING
Email first for anything limited: early access to subscribers is a genuine benefit you promised at signup.
Honouring that is what keeps people subscribed.
For many Nigerian businesses this reaches customers more reliably than email.
Use both. Email is the list you own; WhatsApp is where some customers prefer to be reached.
Do not broadcast on WhatsApp as often as you send email. Tolerance is lower.
WHAT NOT TO DO
Identical text everywhere. Each channel reads differently.
MEASURING
Track which channel produced the response, by asking and by using tracking parameters.