From Signitic, you have the ability to manage all your team members with the buttons on the grouped action bar.
From the "My users" menu accessible from the left sidebar, select your users using the checkboxes to the left of each user or sort them with the filters available at the top of the page.
Then click on the "Export" button on the grouped actions bar.
Once your action has been confirmed, an Excel file will be downloaded with a list of your filtered users' emails.
This allows you, for example, to send a reminder e-mail to users whose plug-in is still not installed!