A software product earns its keep after the signup, not at it. Someone creates an account, looks around for a few minutes, and then either reaches the moment where the tool clicks or drifts away without ever returning. Email is often the only channel that can reach that person once the browser tab is closed, which makes it part of the product experience rather than a side project owned by whoever has spare time.
Behavior beats the calendar
The classic mistake is a drip of day one, day three, day seven messages that ignores what the user already did. A person who connected their data source on the first afternoon does not need a reminder to connect it. A person who never opened the dashboard needs something far simpler than a feature tour. When your app sends events into the email platform (account created, integration connected, first report built, teammate invited), each message can respond to real progress instead of guessing.
Several audiences inside one account
In business software, the person who signed the order, the administrator who configures permissions and the analyst who opens the tool every morning read different things. Sending all of them the same release notes wastes attention. Role and plan data, pulled from your product database or CRM, let us split the program so each group gets content that matches its job.