How do blackouts work?

[Zerohero]

Originally Posted by Dirtbag359

Can someone explain to me how not selling 2,500 tickets leads to a game getting blacked out? I mean I can understand 17,000 unsold tickets but other then that it confuses me how this whole system work. Also I don't get why Fox and CBS can't show two games a piece every week. Why am I stuck watching a Cops marathon half the time?

I've always wondered this. There is only one real day of football, you think we could get two doubleheaders, it's not like they are preempting primetime shows.