Brian Williams, the host of NBC Nightly News, is embroiled in a scandal over fabricated stories he told about experiences during the invasion of Iraq in 2003. He’s taken a leave of absence from the show.

But just how important is an anchor like Williams to a news network in an era of declining network news viewership?

NBC took a ratings hit last week, according to preliminary numbers from Nielsen. It was a big dip, at 36 percent, but declining viewership for network news isn’t exactly, well, news. Fewer and fewer sets are tuned to these broadcasts after reaching a peak in the 1980s.

Is the evening-news tradition becoming irrelevant in this new era of 24/7 information? Or do the networks see a good reason to continue their investment? Williams’ show, after all, is still a major source of ad revenue for NBC.

For more, click on the audio player above.