For sport forums it becomes closer to live text updates for games. People are not so much chatting (although it does occur to an extent, especially at half time), they are instead getting a live text commentary from fellow fans.
Many people will log onto the forum, just to read the live text. Seeing the thoughts and opinions of key match events by key people. Ranging from funny reactions to serious analysis.
If you missed the game, people log on, simply to read the event by event commentary. It great for people at work 
Its more personal/biased than the text commentary from Newspapers or TV channels.