In Snapchat, “by mention” refers when one is tagged or when one’s username is used by another individual in their story or in a conversation. That way it means your username is blinked indicating to you and the other users who has fed on your content.
In the Snapchat application, “mention” refers to the feature of tagging a friend on your story or in the chat section using their account username preceded by “@”. It will be received and the options to open it or reply to it will be available.
