Beginning in 1970, primetime shows needed only worry about losing audience to NFL football games during. Then began in 1987 (initially on ESPN, then shared with TNT, then back to ESPN, before moving to NBC in 2006).
2006 was the same year that the NFL Network's Thursday Night Football telecasts began. At first they weren't much competition, primarily because the NFL Network bungled their carriage strategy and their national reach was very limited, but they've wised up and their reach is on the increase.
NFL Network, % of US TV households:
- June, 2009: 37%
- September, 2009: 41%
- October, 2010: 49%
NFL Network Thursday night games are up 38% in viewership vs. last season (no comparison for adults 18-49 available, but likely similar). About half of that increase can be attributed simply to their increased availability vs. last season. My assumption is that NFL Network availability will continue to slowly increase.
The Colts/Titans game on Thursday, achieved a 2.1 adults 18-49 rating, while being available in just 49% of US TV households via NFL Network. It had more viewers on local broadcast in and Indianapolis, enough to cause Fox and NBC preliminary national ratings to be adjusted downward, but those numbers aren't included in the 2.1 measurement.
That 2.1 rating implies that in the households where NFLN is available it scored more like a 4.2 adults 18-49 rating, which would have topped all Thursday television for the entire primetime period.
Those games are also likely a reason why Thursday broadcast primetime shows have been hitting a string of series low adults 18-49 ratings. Even USA's Burn Notice has hit lows.
Thursday night primetime fades back to pass….sacked by the NFL for a loss!