Mind games are such a key part of the modern game, and here's your opportunity to get involved with some of your own. You can choose whether to comment on your next opponent or previous rival, depending on whether you are trying to gain a psychological edge or simply rub salt in the wound after a previous performance.
Each Comment screen enables you to view an overview of the rival manager who will only take your words as a direct personal reference. Be aware that the bosses' reputation, happiness and relationship with you will not only influence his reponse to your words, but how you are perceived by your own players and everyone else in the Football Manager universe. Criticising a well-regarded old manager who is favoured by your team captain could result in you alienating your own star.
If you wish your comments to have more impact you might consider using the drop-down View menu to make a timely pre- or post-match declaration. These will be made in the pressure cooker atmosphere of the periods either immediately before or after the game.
Note that the release comment feature isn't merely an option to enter into a mud-slinging match with your rivals. Praising another boss or expressing sympathy for their cause could see some of their good reputation rub off on you. Dealing effectively with the comments other managers throw at you will only serve to reflect well on you in your own personal stats.
You'll be given the opportunity to respond to rivals' words in the News section. The effect of your comments and media profile will be reflected in the personal screen of your players and flagged up with a 'PR' icon in the main squad menu.
You don't have to release comments about managers you have recently or are about to square-up against. You can also make a public statement about a boss by clicking the 'Manager Comment' option on the individual's profile screen.