The Ovation Timeline
Ovation allows you to mention project team members in timeline comments. This triggers a notification for the person mentioned, so they'll be informed by Ovation that you've mentioned them, and want to get their attention about something.
To mention a team member, visit any timeline within your project or for a document and simply start typing their first name. A dropdown will appear, revealing all the team members with first names that have the few letters you've type. Select one of those team members, and a "pill" will appear around their name. Once you post the comment, your team member will receive a notification.
Here's how that looks on the project timeline:
Here's how that looks in a file preview page: