I noticed that there is a red icon next to my username. That usually refers to positive, neutral or negative reputation at the other sites that seem to use the same software. Skimming through the threads, it seems like Toucharcade's forum does not use the reputation system, so it is puzzling that it has turned red.
When red it means your not seen by others as logged in. Like an invisible mode. Some people don't want to be bothered by constant pm's or wall posts when on TA. Although I believe you can still click onto their profile to see what thread they're on and tell if they are logged in or not. You probably accidentally activated it.