Use this feature to alert someone about your comment or question!
When you mention someone in the comments section of a routing it will send them a notification email along with your comment.
Here's how you do it
(click below to enlarge):

First: In the comments area: type the "@" symbol and let the names appear.
Second: Type the name you would like send the comment to and click (or use ENTER) to select the highlighted name.
Third: Finish adding the comment and click the paper airplane (or use CTRL+ENTER) to send. The individual will receive an email to let them know about your comment.
This is a great way for you to ask a question, or let someone know some important information about the routing!
Use this feature to alert everyone on a routing.
When you mention someone in the comments section of a routing it will send them a notification email along with your comment. We've now added some new functionality to the mention feature by allowing users to "@all".
This means you can now mention all of your colleagues in a routing by simply typing @all into the timeline.
Navigate to your timeline & at any point while composing your message type @all to notify all of the participants of a routing!

Pro tip: You can highlight & delete the names of individuals you don't want to notify before sending your message.