Ever wanted to mention another Medium user in your story and let them know about it? Now you can—with @ mentions.
Type the "@" symbol and then the name or username of the person you want to mention. You'll see a drop-down list of names as you type.
Once you select a name, the @ symbol will be replaced by their name as a link in green that links to their profile page (http://medium.com/@newwriter, for example).
Mentioning someone will also send them a notification when you publish. Users are able to control notifications from their settings page.
Note: At this time, you have the option in your text to delete the last name of the person in the @ mention (once you've selected their name from the drop-down) to make it more casual, like "Hey Jack" instead of "Hey Jack Dorsey."