Identifying your users will help you find their sessions in the Tolstoy dashboard, and apply specific rules and behaviours on their widget’s display.It’s recommended to call identify right after your user’s signup/login, when you have identifying data to use (such as email, signup date, etc.).
If you know the logged in user you can add his email for better tracking.If you want to add specific Rules & Triggers on users you can skip this and use Identify.