Automated emails
Some events trigger emails to buyers. This lessens the burden of manually keeping buyers updated, and preventing nasty-gram emails.
For instance, if a project's builder logs in and updates a unit's construction phase from "foundation" to "framing", then that will automatically post to the activity tab of your project, but it will also send an email notification to the buyer of that unit. In one action, your marketing is updated, your construction progress analytics are updated, and your buyer is updated!