Another important aspect of marketing, is marketing with existing users, keeping them coming back to the site to make the site more useful and relevant for other users.
Regular e-mails can remind users about the site, if they have forgotten about it, or not had time to visit for a while. We don't want to send them lots of e-mails to nag them into returning, but, we can e-mail them with relevant updates. For example, when someone tries to connect with them on the site, or when they receive a message through the site, we e-mail the user to notify them of this.
This also doubles as a reminder to our users, and if the user connecting with them is of interest to them, it may help members who have lapsed in their interaction with the site to return.