Tonights the night, going to sit down to play some POKER!!!!!!! It's quiet, phone is off, wife & kids went away for the weekend, you get my point. So as you sit there playing in total silence you start to hear the computer fan humming, then its the overhead fan humming at a different pitch, you notice the stack of bills next to the computer, the lights on the printer, the cushion of your chair is worn out, or maybe your system clock is slow again and you wonder why that is.
Now you might find my attention to this sort of detail meaningless, i might not argue the fact, except to say that this sort of detail is present whether you attend to it or not. Your mind picks up on these little details reguardless, maybe not consciously but aware just the same. In live games you can turn your attention to the table to blockout background distractions. At home the table sounds never change, there is no conversation to distract you.
Two reasons to writing this thread, 1st is to mess your head up next time you play online

2nd is to know what people who actually hear these noises do to distract themselves from them.